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<meta name="theme-color" content="#b31b1b">  <title>Search | arXiv e-print repository</title> <script defer src="https://static.arxiv.org/static/base/1.0.0a5/fontawesome-free-5.11.2-web/js/all.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/base/1.0.0a5/css/arxivstyle.css" /> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ messageStyle: "none", extensions: ["tex2jax.js"], jax: ["input/TeX", "output/HTML-CSS"], tex2jax: { inlineMath: [ ['$','$'], ["\$","\$"] ], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEscapes: true, ignoreClass: '.*', processClass: 'mathjax.*' }, TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js"], noErrors: { inlineDelimiters: ["$","$"], multiLine: false, style: { "font-size": "normal", "border": "" } } }, "HTML-CSS": { availableFonts: ["TeX"] } }); </script> <script src='//static.arxiv.org/MathJax-2.7.3/MathJax.js'></script> <script 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</div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.12041">arXiv:2410.12041</a> <span> [<a href="https://arxiv.org/pdf/2410.12041">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Tuning Electric Polarization via Exchange Striction Interaction in CaMn$_7$O$_{12}$ by Sr-Doping </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Nonato%2C+A">A. Nonato</a>, <a href="/search/cond-mat?searchtype=author&query=Vilar%2C+S+Y">S. Y. Vilar</a>, <a href="/search/cond-mat?searchtype=author&query=Mira%2C+J">J. Mira</a>, <a href="/search/cond-mat?searchtype=author&query=Se%C3%B1ar%C3%ADs-Rodr%C3%ADguez%2C+M+A">Mar铆a A. Se帽ar铆s-Rodr铆guez</a>, <a href="/search/cond-mat?searchtype=author&query=and%C3%BAjar%2C+M+S">Manuel S谩nchez and煤jar</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Silva%2C+R+X">R. X. Silva</a>, <a href="/search/cond-mat?searchtype=author&query=Paschoal%2C+C+W+A">C. W. A. Paschoal</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2410.12041v4-abstract-short" style="display: inline;"> Magnetoelectric (ME) materials displaying strong magnetically induced polarization have attracted considerable interest due to their potential applications in spintronics and various fast electrically controlled magnetic devices. CaMn$_7$O$_{12}$ (CMO) stands out for its giant spin-induced ferroelectric polarization. However, the origin of the induced electric polarization in CMO remains highly co… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.12041v4-abstract-full').style.display = 'inline'; document.getElementById('2410.12041v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.12041v4-abstract-full" style="display: none;"> Magnetoelectric (ME) materials displaying strong magnetically induced polarization have attracted considerable interest due to their potential applications in spintronics and various fast electrically controlled magnetic devices. CaMn$_7$O$_{12}$ (CMO) stands out for its giant spin-induced ferroelectric polarization. However, the origin of the induced electric polarization in CMO remains highly controversial and continues to be a subject of ongoing debate. In this paper, through room temperature X-ray powder diffraction (XRPD), temperature-dependent magnetic susceptibility, and thermally stimulated depolarizing current (TSDC) measurements, we provide experimental evidence for a route to tune the magnetically induced polarization by modifying the exchange-striction in CMO via Sr-doping. Our findings demonstrate that the large and broad current peaks observed near the first magnetic phase transition ($T_N1 \sim 90$ K) indicate contributions to the TSDC density from both extrinsic thermally stimulated depolarization processes and intrinsic pyroelectric current arising from magnetically induced polarization changes. We suggest that this reduction in induced electric polarization in CMO originates from the increase in the Mn$^{3+}$ -- O -- Mn$^{4+}$ bond angle due to Sr$^{2+}$ doping, weakening the exchange-striction interaction. Meanwhile, the Dzyaloshinskii-Moriya (DM) effect determines the direction of the induced electric polarization. Our result sheds light on understanding the intriguing giant-induced polarization in CMO and similar compounds with complex magnetic structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.12041v4-abstract-full').style.display = 'none'; document.getElementById('2410.12041v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.10178">arXiv:2403.10178</a> <span> [<a href="https://arxiv.org/pdf/2403.10178">pdf</a>, <a href="https://arxiv.org/format/2403.10178">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Soft Condensed Matter">cond-mat.soft</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Fluid Dynamics">physics.flu-dyn</span> </div> </div> <p class="title is-5 mathjax"> Active nematic-isotropic interfaces on flat surfaces: effects of anchoring, ordering field and activity </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Coelho%2C+R+C+V">Rodrigo C. V. Coelho</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">Jos茅 A. Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Pedro%2C+D+M+C">Duarte M. C. Pedro</a>, <a href="/search/cond-mat?searchtype=author&query=da+Gama%2C+M+M+T">Margarida M. Telo da Gama</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2403.10178v1-abstract-short" style="display: inline;"> A surface in contact with the isotropic phase of a passive liquid crystal can induce nematic order over distances that range from microscopic to macroscopic when the nematic-isotropic interface undergoes an orientational-wetting transition. If the nematic is active, what happens to the interface? Does it propagate and, if it does, is its structure different from the passive one? In this paper, we… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10178v1-abstract-full').style.display = 'inline'; document.getElementById('2403.10178v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.10178v1-abstract-full" style="display: none;"> A surface in contact with the isotropic phase of a passive liquid crystal can induce nematic order over distances that range from microscopic to macroscopic when the nematic-isotropic interface undergoes an orientational-wetting transition. If the nematic is active, what happens to the interface? Does it propagate and, if it does, is its structure different from the passive one? In this paper, we address these questions. We investigate how the active nematic-isotropic interface is affected by the anchoring strength of the surface, the bulk ordering field and the activity. We find that while passive interfaces are one-dimensional the active ones exhibit two dynamical regimes: a passive-like regime and a propagating regime where the interfaces propagate until the entire domain is active nematic. Active interfaces break the translational symmetry within the interfacial plane above a threshold activity, where the active nematic fluctuations, which are ultimately responsible for the emergence of an active turbulent nematic phase, drive non-steady dynamical interfacial regimes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10178v1-abstract-full').style.display = 'none'; document.getElementById('2403.10178v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.02808">arXiv:2401.02808</a> <span> [<a href="https://arxiv.org/pdf/2401.02808">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Two Displacive Ferroelectric Phase Transitions in Multiferroic Quadruple Perovskite $BiMn_{7}O_{12}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Maia%2C+A">A. Maia</a>, <a href="/search/cond-mat?searchtype=author&query=Kempa%2C+M">M. Kempa</a>, <a href="/search/cond-mat?searchtype=author&query=Bovtun%2C+V">V. Bovtun</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Kadlec%2C+C">C. Kadlec</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Belik%2C+A+A">A. A. Belik</a>, <a href="/search/cond-mat?searchtype=author&query=Proschek%2C+P">P. Proschek</a>, <a href="/search/cond-mat?searchtype=author&query=Kamba%2C+S">S. Kamba</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.02808v1-abstract-short" style="display: inline;"> We report on the microwave, terahertz (THz), infrared and Raman spectroscopic studies of $BiMn_{7}O_{12}$ ceramics, shedding more light into the nature of two structural phase transitions and their possible relation with ferroelectricity in this compound. We observed a softening of one polar phonon in the THz range on cooling towards 460 and 300 K, i.e., temperatures at which $BiMn_{7}O_{12}$ unde… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02808v1-abstract-full').style.display = 'inline'; document.getElementById('2401.02808v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.02808v1-abstract-full" style="display: none;"> We report on the microwave, terahertz (THz), infrared and Raman spectroscopic studies of $BiMn_{7}O_{12}$ ceramics, shedding more light into the nature of two structural phase transitions and their possible relation with ferroelectricity in this compound. We observed a softening of one polar phonon in the THz range on cooling towards 460 and 300 K, i.e., temperatures at which $BiMn_{7}O_{12}$ undergoes subsequent structural phase transitions from monoclinic $\textit{I2/m}$ to polar monoclinic $\textit{Im}$ and triclinic $\textit{P1}$ phases. The soft phonon causes dielectric anomalies typical for displacive ferroelectric phase transitions. Microwave measurements performed at 5.8 GHz up to 400 K qualitatively confirmed not only the dielectric anomaly at 300 K, but also revealed two other weak dielectric anomalies near the magnetic phase transitions at 60 K and 28 K. This evidences the multiferroic nature of the low-temperature phases, although the relatively high conductivity in the kHz and Hz spectral range prevented us from directly measuring the permittivity and ferroelectric polarization. Some Raman modes sense the magnetic phase transitions occurring near 60 and 25 K, showing that spin-phonon coupling is relevant in this compound and in this temperature range. The deviation of the Mn-O stretching mode frequency from the anharmonic temperature behavior was successfully explained by the spin correlation function calculated from the magnetic contribution to the specific heat. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02808v1-abstract-full').style.display = 'none'; document.getElementById('2401.02808v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.02802">arXiv:2401.02802</a> <span> [<a href="https://arxiv.org/pdf/2401.02802">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevMaterials.8.084405">10.1103/PhysRevMaterials.8.084405 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Strong impact of low-level substitution of Mn by Fe on the magnetoelectric coupling in $TbMnO_{3}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Maia%2C+A">A. Maia</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Proschek%2C+P">P. Proschek</a>, <a href="/search/cond-mat?searchtype=author&query=Lebeda%2C+M">M. Lebeda</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik</a>, <a href="/search/cond-mat?searchtype=author&query=Manuel%2C+P">P. Manuel</a>, <a href="/search/cond-mat?searchtype=author&query=Khalyavin%2C+D+D">D. D. Khalyavin</a>, <a href="/search/cond-mat?searchtype=author&query=Kamba%2C+S">S. Kamba</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.02802v2-abstract-short" style="display: inline;"> The correlation between static magnetoelectric coupling and magnetic structure was investigated in $TbMn_{0.98}Fe_{0.02}O_{3}$ with magnetic field up to 8 T and down to 2 K. Single-crystal neutron diffraction experiments reveal a substantial increase in the temperature dependence of the incommensurate modulation wave vector of the antiferromagnetic phase as the magnetic field strength increases. M… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02802v2-abstract-full').style.display = 'inline'; document.getElementById('2401.02802v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.02802v2-abstract-full" style="display: none;"> The correlation between static magnetoelectric coupling and magnetic structure was investigated in $TbMn_{0.98}Fe_{0.02}O_{3}$ with magnetic field up to 8 T and down to 2 K. Single-crystal neutron diffraction experiments reveal a substantial increase in the temperature dependence of the incommensurate modulation wave vector of the antiferromagnetic phase as the magnetic field strength increases. Magnetic field-dependent pyroelectric current measurements revealed significantly higher magnetoelectric coupling at magnetic fields below 4 T than in pure TbMnO3. This is due to the higher sensitivity of the incommensurably modulated cycloid structure to weak magnetic fields. Detailed analysis of our data confirmed that the ferroelectric polarization is induced by inverse Dzyaloshinskii-Moriya interaction for magnetic field strength up to 4 T, but at higher fields a departure from theoretical predictions is ascertained, giving evidence for an additional, as yet misunderstood, contribution to magnetoelectric coupling. It shows that a small 2% substitution of Mn3+ by Fe3+ has a strong impact on the magnetic structure, promoting the destabilization of the incommensurably modulated magnetic cycloidal structure of $TbMnO_{3}$ in a magnetic field above 5 T. We demonstrate that the magnetoelectric coupling magnitude can be tuned through suitable substitutional elements, even at low level, inducing local lattice distortions with different electronic and magnetic properties. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02802v2-abstract-full').style.display = 'none'; document.getElementById('2401.02802v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.07029">arXiv:2303.07029</a> <span> [<a href="https://arxiv.org/pdf/2303.07029">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.107.104410">10.1103/PhysRevB.107.104410 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modifying the magnetoelectric coupling in TbMnO$_3$ by low-level Fe$^{3+}$ substitution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Maia%2C+A">A. Maia</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Kadlec%2C+C">C. Kadlec</a>, <a href="/search/cond-mat?searchtype=author&query=Lebeda%2C+M">M. Lebeda</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C%2C+M">M. Mihalik, Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Zentkov%C3%A1%2C+M">M. Zentkov谩</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Kamba%2C+S">S. Kamba</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.07029v1-abstract-short" style="display: inline;"> We report a comprehensive study of the low-level substitution of Mn$^{3+}$ by Fe$^{3+}$ effect on the static and dynamic magnetoelectric coupling in TbMn$_{1-x}$Fe$_x$O$_3$ ($x=0$, 0.02 and 0.04). The cationic substitution has a large impact on the balance between competitive magnetic interactions and, as a result, on the stabilization of the magnetic structures and ferroelectric phase at low temp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.07029v1-abstract-full').style.display = 'inline'; document.getElementById('2303.07029v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.07029v1-abstract-full" style="display: none;"> We report a comprehensive study of the low-level substitution of Mn$^{3+}$ by Fe$^{3+}$ effect on the static and dynamic magnetoelectric coupling in TbMn$_{1-x}$Fe$_x$O$_3$ ($x=0$, 0.02 and 0.04). The cationic substitution has a large impact on the balance between competitive magnetic interactions and, as a result, on the stabilization of the magnetic structures and ferroelectric phase at low temperatures. Low-lying electromagnon excitation is activated in the cycloidal modulated antiferromagnetic and ferroelectric phase in TbMnO$_3$, while it is observed up to TN in the Fe-substituted compounds, pointing for different mechanisms for static and dynamic magnetoelectric coupling. A second electrically active excitation near 40 cm$^{-1}$ is explained by means of Tb3+ crystal-field effects. This excitation is observed up to room temperature, and exhibits a remarkable 15 cm$^{-1}$ downshift on cooling in Fe-substituted compounds. Both electromagnon and crystal-field excitations are found to be coupled to the polar phonons with frequencies up to 250 cm$^{-1}$. Raman spectroscopy reveals a spin-phonon coupling below TN in pure TbMnO$_3$, but the temperature where the coupling start to be relevant increases with Fe concentration and reaches 100 K in TbMn$_{0.96}$Fe$_{0.04}$O$_3$. The anomalies in the T-dependence of magnetic susceptibility above TN are well accounted by spin-phonon coupling and crystal-field excitation, coupled to oxygen motions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.07029v1-abstract-full').style.display = 'none'; document.getElementById('2303.07029v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 107, 104410 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.00386">arXiv:2211.00386</a> <span> [<a href="https://arxiv.org/pdf/2211.00386">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Can the Ferroelectric Soft Mode Trigger an Antiferromagnetic Phase Transition? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Maia%2C+A">Andr茅 Maia</a>, <a href="/search/cond-mat?searchtype=author&query=Kadlec%2C+C">Christelle Kadlec</a>, <a href="/search/cond-mat?searchtype=author&query=Savinov%2C+M">Maxim Savinov</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">Rui Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">Joaquim Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Bovtun%2C+V">Viktor Bovtun</a>, <a href="/search/cond-mat?searchtype=author&query=Kempa%2C+M">Martin Kempa</a>, <a href="/search/cond-mat?searchtype=author&query=M%C3%AD%C5%A1ek%2C+M">Martin M铆拧ek</a>, <a href="/search/cond-mat?searchtype=author&query=Ka%C5%A1til%2C+J">Ji艡铆 Ka拧til</a>, <a href="/search/cond-mat?searchtype=author&query=Prokhorov%2C+A">Andriy Prokhorov</a>, <a href="/search/cond-mat?searchtype=author&query=Ma%C5%88%C3%A1k%2C+J">Jan Ma艌谩k</a>, <a href="/search/cond-mat?searchtype=author&query=Belik%2C+A+A">Alexei A. Belik</a>, <a href="/search/cond-mat?searchtype=author&query=Kamba%2C+S">Stanislav Kamba</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2211.00386v1-abstract-short" style="display: inline;"> Type-II multiferroics, where spin interactions induce a ferroelectric polarization, are interesting for new device functionalities due to large magnetoelectric coupling. We report on a new type of multiferroicity in the quadruple-perovskite $\text{BiMn}_{\text{3}}\text{Cr}_{\text{4}}\text{O}_{\text{12}}$, where an antiferromagnetic phase is induced by the structural change at the ferroelectric pha… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.00386v1-abstract-full').style.display = 'inline'; document.getElementById('2211.00386v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.00386v1-abstract-full" style="display: none;"> Type-II multiferroics, where spin interactions induce a ferroelectric polarization, are interesting for new device functionalities due to large magnetoelectric coupling. We report on a new type of multiferroicity in the quadruple-perovskite $\text{BiMn}_{\text{3}}\text{Cr}_{\text{4}}\text{O}_{\text{12}}$, where an antiferromagnetic phase is induced by the structural change at the ferroelectric phase transition. The displacive nature of the ferroelectric phase transition at 125 K, with a crossover to an order-disorder mechanism, is evidenced by a polar soft phonon in the THz range and a central mode. Dielectric and pyroelectric studies show that the ferroelectric critical temperature corresponds to the previously reported N茅el temperature of the $\text{Cr}^{\text{3+}}$ spins. An increase in ferroelectric polarization is observed below 48 K, coinciding with the N茅el temperature of the $\text{Mn}^{\text{3+}}$ spins. This increase in polarization is attributed to an enhanced magnetoelectric coupling, as no change in the crystal symmetry below 48 K is detected from infrared and Raman spectra. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.00386v1-abstract-full').style.display = 'none'; document.getElementById('2211.00386v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.08267">arXiv:2205.08267</a> <span> [<a href="https://arxiv.org/pdf/2205.08267">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.jpcs.2022.111092">10.1016/j.jpcs.2022.111092 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Lattice dynamics and Raman spectrum of supertetragonal PbVO3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Bouvier%2C+P">Pierre Bouvier</a>, <a href="/search/cond-mat?searchtype=author&query=Sasani%2C+A">Alireza Sasani</a>, <a href="/search/cond-mat?searchtype=author&query=Bousquet%2C+E">Eric Bousquet</a>, <a href="/search/cond-mat?searchtype=author&query=Guennou%2C+M">Mael Guennou</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">Joaquim Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.08267v2-abstract-short" style="display: inline;"> Lead vanadate PbVO3 is a polar crystal with a P4mm space group at ambient conditions. It is isostructural with the model soft-mode driven ferroelectric PbTiO3, but differs from it by the so-called 'supertetragonal' elongation of its unit cell. In this paper, we report a combined study of the lattice dynamics of PbVO3 by Raman spectroscopy at room temperature and first-principle calculations. All z… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.08267v2-abstract-full').style.display = 'inline'; document.getElementById('2205.08267v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.08267v2-abstract-full" style="display: none;"> Lead vanadate PbVO3 is a polar crystal with a P4mm space group at ambient conditions. It is isostructural with the model soft-mode driven ferroelectric PbTiO3, but differs from it by the so-called 'supertetragonal' elongation of its unit cell. In this paper, we report a combined study of the lattice dynamics of PbVO3 by Raman spectroscopy at room temperature and first-principle calculations. All zone-center transverse optical (TO) phonon modes are identified by polarized, angle-dependent Raman spectroscopy and assigned as follows: E modes at 136, 269, 374 and 508 cm-1, A1 modes at 188, 429 and 874 cm-1 and B1 mode at 319 cm-1. The calculations confirm the experimental symmetry assignment and allow to obtain the longitudinal (LO) phonons wavenumbers. Besides, we analyze the mode eigenvectors in detail, in order to identify the atomic displacements associated with each mode and compare them with PbTiO3. In spite of their differences in chemistry and strain, the phonon eigenvectors are found to be remarkably comparable in both compounds. We discuss the position of the ferroelectric soft mode in PbVO3 as compared to PbTiO3. A sizeable splitting of the B1+E modes appears as a characteristic feature of supertetragonal phases. The peculiarity of the vanadyl V-O bond frequency in PbVO3 is also addressed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.08267v2-abstract-full').style.display = 'none'; document.getElementById('2205.08267v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 8 figures, 6 Tables, Supplemental Information 3 figures and 6 Tables, under review</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1901.06119">arXiv:1901.06119</a> <span> [<a href="https://arxiv.org/pdf/1901.06119">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.99.064109">10.1103/PhysRevB.99.064109 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Crossover in the pressure evolution of elementary distortions in RFeO3 perovskites and its impact on their phase transition </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Bouvier%2C+P">P. Bouvier</a>, <a href="/search/cond-mat?searchtype=author&query=Guennou%2C+M">M. Guennou</a>, <a href="/search/cond-mat?searchtype=author&query=Peral%2C+I">I. Peral</a>, <a href="/search/cond-mat?searchtype=author&query=Weber%2C+M+C">M. C. Weber</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P">P. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik</a>, <a href="/search/cond-mat?searchtype=author&query=Garbarino%2C+G">G. Garbarino</a>, <a href="/search/cond-mat?searchtype=author&query=Mezouar%2C+M">M. Mezouar</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1901.06119v1-abstract-short" style="display: inline;"> This work reports on the pressure dependence of the octahedra tilts and mean Fe-O bond lengths in RFeO3 (R=Nd, Sm, Eu, Gd, Tb and Dy), determined through synchrotron X-ray diffraction and Raman scattering, and their role on the pressure induced phase transition displayed by all of these compounds. For larger rare-earth cations (Nd-Sm), both anti- and in-phase octahedra tilting decrease as pressure… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.06119v1-abstract-full').style.display = 'inline'; document.getElementById('1901.06119v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1901.06119v1-abstract-full" style="display: none;"> This work reports on the pressure dependence of the octahedra tilts and mean Fe-O bond lengths in RFeO3 (R=Nd, Sm, Eu, Gd, Tb and Dy), determined through synchrotron X-ray diffraction and Raman scattering, and their role on the pressure induced phase transition displayed by all of these compounds. For larger rare-earth cations (Nd-Sm), both anti- and in-phase octahedra tilting decrease as pressure increases, whereas the reverse behavior is observed for smaller ones (Gd-Dy). EuFeO3 stands at the borderline, as the tilts are pressure independent. For the compounds where the tilts increase with pressure, the FeO6 octahedra are compressed at lower rates than for those ones exhibiting opposite pressure tilt dependence. The crossover between the two opposite pressure behaviors is discussed and faced with the rules grounded on the current theoretical approaches. The similarity of the pressure-induced isostructural insulator-to-metal phase transition, observed in the whole series, point out that the tilts play a minor role in its driving mechanisms. A clear relationship between octahedra compressibility and critical pressure is ascertained. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.06119v1-abstract-full').style.display = 'none'; document.getElementById('1901.06119v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages (including Supplemental Information), 12 figures and 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 99, 064109 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.07987">arXiv:1609.07987</a> <span> [<a href="https://arxiv.org/pdf/1609.07987">pdf</a>, <a href="https://arxiv.org/ps/1609.07987">ps</a>, <a href="https://arxiv.org/format/1609.07987">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.94.214103">10.1103/PhysRevB.94.214103 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Raman spectroscopy of rare-earth orthoferrites RFeO3 (R = La, Sm, Eu, Gd, Tb, Dy) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Weber%2C+M+C">Mads Christof Weber</a>, <a href="/search/cond-mat?searchtype=author&query=Guennou%2C+M">Mael Guennou</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+H+J">Hong Jian Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=%C3%8D%C3%B1iguez%2C+J">Jorge 脥帽iguez</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">Rui Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">Ab铆lio Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">Joaquim Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">Jens Kreisel</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.07987v1-abstract-short" style="display: inline;"> We report a Raman scattering study of six rare earth orthoferrites RFeO3, with R = La, Sm, Eu, Gd, Tb, Dy. The use of extensive polarized Raman scattering of SmFeO3 and first-principles calculations enable the assignment of the observed phonon modes to vibrational symmetries and atomic displacements. The assignment of the spectra and their comparison throughout the whole series allows correlating… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07987v1-abstract-full').style.display = 'inline'; document.getElementById('1609.07987v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.07987v1-abstract-full" style="display: none;"> We report a Raman scattering study of six rare earth orthoferrites RFeO3, with R = La, Sm, Eu, Gd, Tb, Dy. The use of extensive polarized Raman scattering of SmFeO3 and first-principles calculations enable the assignment of the observed phonon modes to vibrational symmetries and atomic displacements. The assignment of the spectra and their comparison throughout the whole series allows correlating the phonon modes with the orthorhombic structural distortions of RFeO3 perovskites. In particular, the positions of two specific Ag modes scale linearly with the two FeO6 octahedra tilt angles, allowing the distortion throughout the series. At variance with literature, we find that the two octahedra tilt angles scale differently with the vibration frequencies of their respective Ag modes. This behavior as well as the general relations between the tilt angles, the frequencies of the associated modes and the ionic radii are rationalized in a simple Landau model. The reported Raman spectra and associated phonon-mode assignment provide reference data for structural investigations of the whole series of orthoferrites. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.07987v1-abstract-full').style.display = 'none'; document.getElementById('1609.07987v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 94, 214103 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.02503">arXiv:1605.02503</a> <span> [<a href="https://arxiv.org/pdf/1605.02503">pdf</a>, <a href="https://arxiv.org/ps/1605.02503">ps</a>, <a href="https://arxiv.org/format/1605.02503">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Magnetic phase diagram of TbMn$_{1-x}$Fe$_x$O$_3$ $(0 \leq x \leq 1)$ substitutional solid solution </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik</a>, <a href="/search/cond-mat?searchtype=author&query=Jaglicic%2C+Z">Z. Jaglicic</a>, <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Queiros%2C+E">E. Queiros</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Zentkova%2C+M">M. Zentkova</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1605.02503v2-abstract-short" style="display: inline;"> We present the magnetic phase diagram of TbMn1-xFexO3 substitutional solid solution in the whole concentration range 0 <= x <= 1 as determined from magnetization and specific heat measurements. We have found that the dominant magnetic ion in the concentration range 0 <= x < 0.3 is manganese, while iron ions do not create independent magnetic structure, but strongly affect magnetic properties of th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.02503v2-abstract-full').style.display = 'inline'; document.getElementById('1605.02503v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.02503v2-abstract-full" style="display: none;"> We present the magnetic phase diagram of TbMn1-xFexO3 substitutional solid solution in the whole concentration range 0 <= x <= 1 as determined from magnetization and specific heat measurements. We have found that the dominant magnetic ion in the concentration range 0 <= x < 0.3 is manganese, while iron ions do not create independent magnetic structure, but strongly affect magnetic properties of the parent compound by reducing transition to magnetically ordered state and transition into a cycloidal phase. The magnetism in the concentration range 0.3 < x <= 1 is driven by the Fe sublattice. The manganese ions again do not order in long range magnetic ordered state, but stabilize four different magnetic structures of Fe sublattice above 2 K. The magnetic ordering of Tb sublattice was observed only on parent compounds TbMnO3 and TbFeO3 and for doping level below 0.1, or over 0.9. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.02503v2-abstract-full').style.display = 'none'; document.getElementById('1605.02503v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2016. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1603.06423">arXiv:1603.06423</a> <span> [<a href="https://arxiv.org/pdf/1603.06423">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Ferroelectric imprint in annealed Bi0.9La0.1Fe0.9Mn0.1O3 thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Carvalho%2C+T+T">T. T. Carvalho</a>, <a href="/search/cond-mat?searchtype=author&query=Figueiras%2C+F+G">F. G. Figueiras</a>, <a href="/search/cond-mat?searchtype=author&query=Garcia%2C+M+P+F">M. P. F. Garcia</a>, <a href="/search/cond-mat?searchtype=author&query=Pereira%2C+A+M">A. M. Pereira</a>, <a href="/search/cond-mat?searchtype=author&query=Fernandes%2C+J+R+A">J. R. A. Fernandes</a>, <a href="/search/cond-mat?searchtype=author&query=de+la+Cruz%2C+J+P">J. Perez de la Cruz</a>, <a href="/search/cond-mat?searchtype=author&query=Pereira%2C+S+M+S">S. M. S. Pereira</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1603.06423v1-abstract-short" style="display: inline;"> The present work reports the study of the optimized processing conditions of Bi0.9La0.1Fe0.9Mn0.1O3 thin films, grown by RF sputtering on platinum metalized silicon substrates. The combination of deposition at relatively low substrate temperature followed by adequate ex situ annealing leads to thin films with smooth surface morphology and the formation of a high-quality monophasic layer, with the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.06423v1-abstract-full').style.display = 'inline'; document.getElementById('1603.06423v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1603.06423v1-abstract-full" style="display: none;"> The present work reports the study of the optimized processing conditions of Bi0.9La0.1Fe0.9Mn0.1O3 thin films, grown by RF sputtering on platinum metalized silicon substrates. The combination of deposition at relatively low substrate temperature followed by adequate ex situ annealing leads to thin films with smooth surface morphology and the formation of a high-quality monophasic layer, with the (100)c preferable orientation. The annealed films show ferroelectric imprint. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1603.06423v1-abstract-full').style.display = 'none'; document.getElementById('1603.06423v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2016. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.01574">arXiv:1602.01574</a> <span> [<a href="https://arxiv.org/pdf/1602.01574">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.jmmm.2017.04.085">10.1016/j.jmmm.2017.04.085 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the ferroelectric and magnetoelectric mechanisms in low Fe$^{3+}$ doped TbMnO$_3$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Queiros%2C+E">E. Queiros</a>, <a href="/search/cond-mat?searchtype=author&query=Passos%2C+D+J">D. J. Passos</a>, <a href="/search/cond-mat?searchtype=author&query=Mota%2C+D+A">D. A. Mota</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Zentkova%2C+M">M. Zentkova</a>, <a href="/search/cond-mat?searchtype=author&query=Mihalik%2C+M">M. Mihalik</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.01574v2-abstract-short" style="display: inline;"> This work addresses the effect of substituting Mn$^{3+}$ by Fe$^{3+}$ at the octahedral site of TbMnO$_3$ on the magnetic phase sequence, ferroelectric and magnetoelectric properties, keeping the Fe$^{3+}$ concentration below 5%. The temperature dependence of the specific heat, dielectric permittivity and electric polarization was studied as a function of Fe$^{3+}$ concentration and applied magnet… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01574v2-abstract-full').style.display = 'inline'; document.getElementById('1602.01574v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.01574v2-abstract-full" style="display: none;"> This work addresses the effect of substituting Mn$^{3+}$ by Fe$^{3+}$ at the octahedral site of TbMnO$_3$ on the magnetic phase sequence, ferroelectric and magnetoelectric properties, keeping the Fe$^{3+}$ concentration below 5%. The temperature dependence of the specific heat, dielectric permittivity and electric polarization was studied as a function of Fe$^{3+}$ concentration and applied magnetic field. From the experimental results a strong decrease of the electric polarization with increasing Fe$^{3+}$ substitution is observed, vanishing above a concentration of 4%. However, within this range, a significant increase of the magnetic sensitivity of the electric polarization is obtained by increasing Fe$^{3+}$ concentration. Above that value, a non-polar, weak ferromagnetic phase emerges, in good agreement with the predictions of the Dzyalowshinskii-Moriya model. This behavior reveals the crucial effect of Fe$^{3+}$ substitution in octahedral sites on the magnetic phase sequence, polar and magnetoelectric behavior of the TbMn$_{1-x}$Fe$_x$O$_3$ system. From the results obtained in this work, it is understood that this behavior is not associated with the eg electronic configuration, but instead to the competition between ferromagnetic and antiferromagnetic interactions, which is very sensitive to both local fields and distortions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.01574v2-abstract-full').style.display = 'none'; document.getElementById('1602.01574v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Magnetism and Magnetic Materials 439, 167-172 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.8350">arXiv:1412.8350</a> <span> [<a href="https://arxiv.org/pdf/1412.8350">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Structural properties and spin-phonon coupling in orthorhombic Y-substituted GdMnO$_{3}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Queir%C3%B3s%2C+E+C">E. C. Queir贸s</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.8350v2-abstract-short" style="display: inline;"> We present a systematic study of the structure and lattice dynamics at room temperature, and the phonon behavior at low temperatures in orthorhombic Gd$_{1-x}$Y$_{x}$MnO$_{3}$ manganites, with 0 $\leq$ x $\leq$ 0.4, using powder x-ray diffraction and Raman scattering. A thorough analysis towards the correlation between both structural and Raman modes parameters was undertaken. The data obtained at… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.8350v2-abstract-full').style.display = 'inline'; document.getElementById('1412.8350v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.8350v2-abstract-full" style="display: none;"> We present a systematic study of the structure and lattice dynamics at room temperature, and the phonon behavior at low temperatures in orthorhombic Gd$_{1-x}$Y$_{x}$MnO$_{3}$ manganites, with 0 $\leq$ x $\leq$ 0.4, using powder x-ray diffraction and Raman scattering. A thorough analysis towards the correlation between both structural and Raman modes parameters was undertaken. The data obtained at room temperature reveal structural distortions arising from the Jahn-Teller distortion and octahedra tilting. The Jahn-Teller distortion is apparently x-independent, while an increase of Mn-O1-Mn bond angle of about 0.5掳 could be ascertain when x changes from 0 to 0.4. Spin-phonon coupling was evidenced from the Raman results. The temperature dependence of the B1g in-plane O2 stretching mode of the MnO6 octahedron has revealed either a positive or negative shift regarding the pure anharmonic temperature dependence of the phonon frequency, which strongly depends on the Y-concentration. The frequency renormalization is explained in terms of a competition between ferro and antiferromagnetic interactions. The ratio between the spin-phonon coupling constant and the effective magnetic exchange integral per spin was determined from the renormalized wave number of the in-plane O2 stretching mode, associated with the spin-spin correlation function. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.8350v2-abstract-full').style.display = 'none'; document.getElementById('1412.8350v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Version with Supplemental Material</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.6987">arXiv:1402.6987</a> <span> [<a href="https://arxiv.org/pdf/1402.6987">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.90.054104">10.1103/PhysRevB.90.054104 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dynamic and structural properties of orthorhombic rare-earth manganites under high pressure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mota%2C+D+A">D. A. Mota</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Rodrigues%2C+V+H">V. H. Rodrigues</a>, <a href="/search/cond-mat?searchtype=author&query=Costa%2C+M+M+R">M. M. R. Costa</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P">P. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Bouvier%2C+P">P. Bouvier</a>, <a href="/search/cond-mat?searchtype=author&query=Guennou%2C+M">M. Guennou</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.6987v1-abstract-short" style="display: inline;"> We report a high-pressure study of orthorhombic rare-earth manganites AMnO3 using Raman scattering (for A = Pr, Nd, Sm, Eu, Tb and Dy) and synchrotron X-ray diffraction (for A = Pr, Sm, Eu, and Dy). In all cases, a structural and insulator-to-metal transition was evidenced, with a critical pressure that depends on the A-cation size. We analyze the compression mechanisms at work in the different ma… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6987v1-abstract-full').style.display = 'inline'; document.getElementById('1402.6987v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.6987v1-abstract-full" style="display: none;"> We report a high-pressure study of orthorhombic rare-earth manganites AMnO3 using Raman scattering (for A = Pr, Nd, Sm, Eu, Tb and Dy) and synchrotron X-ray diffraction (for A = Pr, Sm, Eu, and Dy). In all cases, a structural and insulator-to-metal transition was evidenced, with a critical pressure that depends on the A-cation size. We analyze the compression mechanisms at work in the different manganites via the pressure dependence of the lattice parameters, the shear strain in the a-c plane, and the Raman bands associated with out-of-phase MnO6 rotations and in-plane O2 symmetric stretching modes. Our data show a crossover across the rare-earth series between two different kinds of behavior. For the smallest A-cations, the compression is nearly isotropic in the ac plane, with presumably only very slight changes of tilt angles and Jahn-Teller distortion. As the radius of the A-cation increases, the pressure-induced reduction of Jahn-Teller distortion becomes more pronounced and increasingly significant as a compression mechanism, while the pressure-induced bending of octahedra chains becomes conversely less pronounced. We finally discuss our results in the light of the notion of chemical pressure, and show that the analogy with hydrostatic pressure works quite well for manganites with small A-cations but can be misleading with large A-cations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6987v1-abstract-full').style.display = 'none'; document.getElementById('1402.6987v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.4040">arXiv:1402.4040</a> <span> [<a href="https://arxiv.org/pdf/1402.4040">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0022-3727/47/43/435002">10.1088/0022-3727/47/43/435002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unravelling the effect of SrTiO3 antiferrodistortive phase transition on the magnetic properties of La0.7Sr0.3MnO3 thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mota%2C+D+A">D. A. Mota</a>, <a href="/search/cond-mat?searchtype=author&query=Barcelay%2C+Y+R">Y. Romaguera Barcelay</a>, <a href="/search/cond-mat?searchtype=author&query=Senos%2C+A+M+R">A. M. R. Senos</a>, <a href="/search/cond-mat?searchtype=author&query=Fernandes%2C+C+M">C. M. Fernandes</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Gomes%2C+I+T">I. T. Gomes</a>, <a href="/search/cond-mat?searchtype=author&query=S%C3%A1%2C+P">P. S谩</a>, <a href="/search/cond-mat?searchtype=author&query=Fernandes%2C+L">L. Fernandes</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+B+G">B. G. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Figueiras%2C+F">F. Figueiras</a>, <a href="/search/cond-mat?searchtype=author&query=Vaghefi%2C+P+M">P. Mirzadeh Vaghefi</a>, <a href="/search/cond-mat?searchtype=author&query=Amaral%2C+V+S">V. S. Amaral</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=de+la+Cruz%2C+J+P">J. P茅rez de la Cruz</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.4040v1-abstract-short" style="display: inline;"> Epitaxial La0.7Sr0.3MnO3 (LSMO) thin films, with different thickness ranging from 20 nm up to 330 nm, were deposited on (100)-oriented strontium titanate (STO) substrates by pulsed laser deposition, and their structure and morphology characterized at room temperature. Magnetic and electric transport properties of the as-processed thin films reveal an abnormal behavior in the temperature dependent… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.4040v1-abstract-full').style.display = 'inline'; document.getElementById('1402.4040v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.4040v1-abstract-full" style="display: none;"> Epitaxial La0.7Sr0.3MnO3 (LSMO) thin films, with different thickness ranging from 20 nm up to 330 nm, were deposited on (100)-oriented strontium titanate (STO) substrates by pulsed laser deposition, and their structure and morphology characterized at room temperature. Magnetic and electric transport properties of the as-processed thin films reveal an abnormal behavior in the temperature dependent magnetization M(T) below the antiferrodistortive STO phase transition (TSTO) and also an anomaly in the magnetoresistance and electrical resistivity close to the same temperature. Up to 100 nm LSMO thin films, an in-excess magnetization and pronounced changes in the coercivity are evidenced, achieved through the interface-mediated magnetoelastic coupling with antiferrodistortive domain wall movement occurring below TSTO. Contrarily, for thicker LSMO thin films, above 100 nm, an in-defect magnetization is observed. This reversed behavior can be understood within the emergence in the upper layer of the film, observed by high resolution transmission electron microscopy, of a branched structure needed to relax elastic energy stored in the film which leads to randomly oriented magnetic domain reconstructions. For enough high-applied magnetic fields, as thermodynamic equilibrium is reached, a fully suppression of the anomalous magnetization occurs, wherein the temperature dependence of the magnetization starts to follow the expected Brillouin behavior. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.4040v1-abstract-full').style.display = 'none'; document.getElementById('1402.4040v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 17 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 9 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1401.5718">arXiv:1401.5718</a> <span> [<a href="https://arxiv.org/pdf/1401.5718">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.ssc.2015.02.013">10.1016/j.ssc.2015.02.013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dzyaloshinskii-Moriya nature of ferroelectric ordering in magnetoelectric Gd$_{1-x}$Y$_{x}$MnO$_{3}$ system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Vilarinho%2C+R">R. Vilarinho</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=da+Silva%2C+J+M+M">J. M. Machado da Silva</a>, <a href="/search/cond-mat?searchtype=author&query=Oliveira%2C+J+B">J. B. Oliveira</a>, <a href="/search/cond-mat?searchtype=author&query=S%C3%A1%2C+M+A">M. A. S谩</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1401.5718v2-abstract-short" style="display: inline;"> This work reports on magnetic, dielectric, thermodynamic and magnetoelectric properties of Gd$_{1-x}$Y$_{x}$MnO$_{3}$, with 0 \leq x \leq 0.4, with emphasis on the (x, T) phase diagram, towards unraveling the role of the driving mechanisms in stabilizing both magnetic and ferroelectric orderings. The (x, T) phase diagram reflects the effect of lattice distortions induced by the substitution of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.5718v2-abstract-full').style.display = 'inline'; document.getElementById('1401.5718v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1401.5718v2-abstract-full" style="display: none;"> This work reports on magnetic, dielectric, thermodynamic and magnetoelectric properties of Gd$_{1-x}$Y$_{x}$MnO$_{3}$, with 0 \leq x \leq 0.4, with emphasis on the (x, T) phase diagram, towards unraveling the role of the driving mechanisms in stabilizing both magnetic and ferroelectric orderings. The (x, T) phase diagram reflects the effect of lattice distortions induced by the substitution of $Gd^{3+}$ ion by smaller $Y^{3+}$ ion, which gradually unbalances the antiferromagnetic against the ferromagnetic exchange interactions, enabling the emergence of ferroelectricity for higher concentrations of yttrium. For $x \leq 0.1$, the paramagnetic phase is followed by a presumably incommensurate collinear antiferromagnetic phase, then a weak ferromagnetic canted A-type antiferromagnetic ordering is established at lower temperatures.For $0.2 \leq x \leq 0.4$, a different phase sequence is obtained. The canted A-type antiferromagnetic arrangement is no more stable, and instead a pure antiferromagnetic ordering is stabilized below T$_{lock}$ $\approx$ 14 - 17 K, with an improper ferroelectric character. From these results, a cycloid modulated spin arrangement at low temperatures is proposed, accordingly to the inverse Dzyaloshinskii Moriya model. Anomalous temperature dependence of the dipolar relaxation energy and magnetization evidence for structural and magnetic changes occurring at $T* \approx 22 - 28 K$, for $0.1 \leq x \leq 0.4$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1401.5718v2-abstract-full').style.display = 'none'; document.getElementById('1401.5718v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 January, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 9 figures. Results replaced in section 3d, and revised arguments. Number of figures reduced</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1309.7243">arXiv:1309.7243</a> <span> [<a href="https://arxiv.org/pdf/1309.7243">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1016/j.tsf.2014.06.007">10.1016/j.tsf.2014.06.007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Structural, electrical and magnetic properties of magnetoelectric GdMnO3 thin films prepared by sol-gel method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Romaguera-Barcelay%2C+Y">Y. Romaguera-Barcelay</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=de+la+Cruz%2C+J+P">J. P茅rez de la Cruz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1309.7243v1-abstract-short" style="display: inline;"> In this work, we analysed GdMnO3 magnetoelectric thin films prepared by a general sol-gel method. The film formation temperature is analysed by termogravimetric analysis, while the lattice parameters of the Pbnm orthorhombic films are determined from the analysis of the x-ray spectra. The x-ray results also reveal that GdMnO3 films are under compression along the b axis. The lattice dynamic analys… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.7243v1-abstract-full').style.display = 'inline'; document.getElementById('1309.7243v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1309.7243v1-abstract-full" style="display: none;"> In this work, we analysed GdMnO3 magnetoelectric thin films prepared by a general sol-gel method. The film formation temperature is analysed by termogravimetric analysis, while the lattice parameters of the Pbnm orthorhombic films are determined from the analysis of the x-ray spectra. The x-ray results also reveal that GdMnO3 films are under compression along the b axis. The lattice dynamic analysis carried out by Raman spectroscopy confirms the formation of films with a Pbnm orthorhombic structure. Moreover, the analysis of the Raman spectra suggests that besides film-substrate interaction, texture and grain size influence can alters lattice dynamics relative to bulk ones. Magnetic measurements shows that the films response is different of the observed in ceramic and single crystal; mainly, in the shape and temperature where the transitions taking place. The magnetic study also reveals that GdMnO3 films are paramagnetic above 80 K, showing a ferromagnetic response at low temperatures (T=<15 K). The dielectric analysis carried out in the 850C annealed films shows the formation of a relaxation process at low temperature, which is associated with a polaronic process. Moreover, it is also observed a small anomaly at T~27 K that might be related with the magnetic transition taking place in this temperature range. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.7243v1-abstract-full').style.display = 'none'; document.getElementById('1309.7243v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 September, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2013. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1208.2336">arXiv:1208.2336</a> <span> [<a href="https://arxiv.org/pdf/1208.2336">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0953-8984/25/23/235602">10.1088/0953-8984/25/23/235602 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Competing exchanges and spin-phonon coupling in Eu1-xRxMnO3 (R=Y,Lu) </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Mota%2C+D+A">D. A. Mota</a>, <a href="/search/cond-mat?searchtype=author&query=Barcelay%2C+Y+R">Y. Romaguera Barcelay</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Oliveira%2C+J">J. Oliveira</a>, <a href="/search/cond-mat?searchtype=author&query=Ferreira%2C+W+S">W. S. Ferreira</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1208.2336v1-abstract-short" style="display: inline;"> This work is focused on the phase diagrams and physical properties of Y-doped and Lu-doped EuMnO3. The differences in the corresponding phase boundaries in the (x,T) phase diagram could be overcome by considering a scaling of the Y3+ and Lu3+ concentrations to the tolerance factor. This outcome evidences that the tolerance factor is in fact a more reliable representative of the lattice deformation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1208.2336v1-abstract-full').style.display = 'inline'; document.getElementById('1208.2336v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1208.2336v1-abstract-full" style="display: none;"> This work is focused on the phase diagrams and physical properties of Y-doped and Lu-doped EuMnO3. The differences in the corresponding phase boundaries in the (x,T) phase diagram could be overcome by considering a scaling of the Y3+ and Lu3+ concentrations to the tolerance factor. This outcome evidences that the tolerance factor is in fact a more reliable representative of the lattice deformation induced by doping. The normalization of the phase boundaries using the tolerance factor corroborates previous theoretical outcomes regarding the key role of competitive FM and AFM exchanges in determining the phase diagrams of manganite perovskites. Though, significant differences in the nature and number of phases at low temperatures and concentrations could not be explained by just considering the normalization to the tolerance factor. The vertical phase boundary observed just for Lu-doped EuMnO3, close to 10%Lu, is understood considering a low temperature Peierls-type spin-phonon coupling, which stabilizes the AFM4 phase in Lu-doped EuMnO3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1208.2336v1-abstract-full').style.display = 'none'; document.getElementById('1208.2336v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 August, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2012. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 6 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1111.4855">arXiv:1111.4855</a> <span> [<a href="https://arxiv.org/pdf/1111.4855">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Structural and insulator-to-metal phase transition at 50 GPa in GdMnO3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Oliveira%2C+J">J. Oliveira</a>, <a href="/search/cond-mat?searchtype=author&query=Rodrigues%2C+V+H">V. H. Rodrigues</a>, <a href="/search/cond-mat?searchtype=author&query=Costa%2C+M+M+R">M. M. R. Costa</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a>, <a href="/search/cond-mat?searchtype=author&query=Bouvier%2C+P">P. Bouvier</a>, <a href="/search/cond-mat?searchtype=author&query=Guennou%2C+M">M. Guennou</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1111.4855v1-abstract-short" style="display: inline;"> We present a study of the effect of very high pressure on the orthorhombic perovskite GdMnO3 by Raman spectroscopy and synchrotron x-ray diffraction up to 53.2 GPa. The experimental results yield a structural and insulator-to-metal phase transition close to 50 GPa, from an orthorhombic to a metrically cubic structure. The phase transition is of first order with a pressure hysteresis of about 6 GPa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1111.4855v1-abstract-full').style.display = 'inline'; document.getElementById('1111.4855v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1111.4855v1-abstract-full" style="display: none;"> We present a study of the effect of very high pressure on the orthorhombic perovskite GdMnO3 by Raman spectroscopy and synchrotron x-ray diffraction up to 53.2 GPa. The experimental results yield a structural and insulator-to-metal phase transition close to 50 GPa, from an orthorhombic to a metrically cubic structure. The phase transition is of first order with a pressure hysteresis of about 6 GPa. The observed behavior under very high pressure might well be a general feature in rare-earth manganites. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1111.4855v1-abstract-full').style.display = 'none'; document.getElementById('1111.4855v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 pages, 3 figures and 2 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1111.4854">arXiv:1111.4854</a> <span> [<a href="https://arxiv.org/pdf/1111.4854">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0953-8984/24/43/436002">10.1088/0953-8984/24/43/436002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magentically-Induced Lattice Distortions and Ferroelectricity in Magnetoelectric GdMnO3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Oliveira%2C+J">J. Oliveira</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a>, <a href="/search/cond-mat?searchtype=author&query=Carpinteiro%2C+F">F. Carpinteiro</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1111.4854v1-abstract-short" style="display: inline;"> In this work we investigate the magnetic field dependence of Ag octahedra rotation (tilt) and B2g symmetric stretching modes frequency at different temperatures. Our field-dependent Raman investigation at 10K is interpreted by an ionic displacive nature of the magnetically induced ferroelectric phase transition. The frequency change of the Ag tilt is in agreement with the stabilization of the Mn-G… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1111.4854v1-abstract-full').style.display = 'inline'; document.getElementById('1111.4854v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1111.4854v1-abstract-full" style="display: none;"> In this work we investigate the magnetic field dependence of Ag octahedra rotation (tilt) and B2g symmetric stretching modes frequency at different temperatures. Our field-dependent Raman investigation at 10K is interpreted by an ionic displacive nature of the magnetically induced ferroelectric phase transition. The frequency change of the Ag tilt is in agreement with the stabilization of the Mn-Gd spin arrangement, yielding the necessary conditions for the onset of ferroelectricity on the basis of the inverse Dzyaloshinskii-Moriya interaction. The role of the Jahn-Teller cooperative interaction is also evidenced by the change of the B2g mode frequency at the ferroelectric phase transition. This frequency change allows estimating the shift of the oxygen position at the ferroelectric phase transition and the corresponding spontaneous polarization of 480 渭C/m2, which agrees with earlier reported values in single crystals. Our study also confirms the existence of a large magnetic hysteresis at the lowest temperatures, which is a manifestation of magnetrostiction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1111.4854v1-abstract-full').style.display = 'none'; document.getElementById('1111.4854v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 November, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2011. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">5 pages, 3 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1006.4963">arXiv:1006.4963</a> <span> [<a href="https://arxiv.org/pdf/1006.4963">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1080/01411594.2010.509603">10.1080/01411594.2010.509603 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> THz and infrared studies of multiferroic hexagonal Y_(1-x)Eu_xMnO_3 (x=0 - 0.2) ceramics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Goian%2C+V">V. Goian</a>, <a href="/search/cond-mat?searchtype=author&query=Kamba%2C+S">S. Kamba</a>, <a href="/search/cond-mat?searchtype=author&query=Kadlec%2C+C">C. Kadlec</a>, <a href="/search/cond-mat?searchtype=author&query=Nuzhnyy%2C+D">D. Nuzhnyy</a>, <a href="/search/cond-mat?searchtype=author&query=Kuzel%2C+P">P. Kuzel</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1006.4963v1-abstract-short" style="display: inline;"> We report an investigation of hexagonal Y_(1-x)Eu_xMnO_3 ceramics with x=0, 0.1 and 0.2 using infrared and THz spectroscopies in the temperature range between 5 and 900 K. The temperature dependence of the THz permittivity reveals a kink near the antiferromagnetic phase transition temperature T_N ~ 70 K giving evidence of a strong spin-lattice coupling. Below T_N two absorption peaks were revealed… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1006.4963v1-abstract-full').style.display = 'inline'; document.getElementById('1006.4963v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1006.4963v1-abstract-full" style="display: none;"> We report an investigation of hexagonal Y_(1-x)Eu_xMnO_3 ceramics with x=0, 0.1 and 0.2 using infrared and THz spectroscopies in the temperature range between 5 and 900 K. The temperature dependence of the THz permittivity reveals a kink near the antiferromagnetic phase transition temperature T_N ~ 70 K giving evidence of a strong spin-lattice coupling. Below T_N two absorption peaks were revealed in the THz spectra close to 43 and 73 cm-1. While the first peak corresponds to a sharp antiferromagnetic resonance exhibiting softening on heating towards TN, the second one may be attributed to an impurity mode or a multiphonon absorption peak. High-temperature THz spectra measured up to 900 K reveal only small gradual increase of the permittivity in agreement with a weak phonon softening observed in the infrared reflectance spectra upon heating. This corresponds to an improper ferroelectric character of the phase transition proposed from first principle calculations by Fennie and Rabe [Phys. Rev. B 72 (2005), pp. 100103(R)]. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1006.4963v1-abstract-full').style.display = 'none'; document.getElementById('1006.4963v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 June, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Phase Transitions, accepted</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phase Transitions 83, 931-941 (2010) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1005.5465">arXiv:1005.5465</a> <span> [<a href="https://arxiv.org/pdf/1005.5465">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Biological Physics">physics.bio-ph</span> </div> </div> <p class="title is-5 mathjax"> Synthesis and characterization of HAp nanorods from a cationic surfactant template method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Coelho%2C+J+M">J. M. Coelho</a>, <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Monteiro%2C+F+J">F. J. Monteiro</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1005.5465v1-abstract-short" style="display: inline;"> Hydroxyapatite (HAp) [Ca10(PO4)6(OH)2] nanorods were synthesized using a surfactant templating method, with cetyltrimethylammonium bromide (CTAB) micelles acting as template for HAp growth. The effects of the sintering temperature on the morphological and crystallographic characteristics and on chemical composition of the "as-prepared" structures are discussed. The experimental results show that l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1005.5465v1-abstract-full').style.display = 'inline'; document.getElementById('1005.5465v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1005.5465v1-abstract-full" style="display: none;"> Hydroxyapatite (HAp) [Ca10(PO4)6(OH)2] nanorods were synthesized using a surfactant templating method, with cetyltrimethylammonium bromide (CTAB) micelles acting as template for HAp growth. The effects of the sintering temperature on the morphological and crystallographic characteristics and on chemical composition of the "as-prepared" structures are discussed. The experimental results show that low heat-treatment temperatures are preferred in order to obtain high quality nanorods, with diameters ranging between 20 nm and 50 nm. High heat-treatment temperatures enhance the thermal decomposition of HAp into other calcium phosphate compounds, and the sintering of particles into micrometer ball-like structures. The stability of aqueous suspensions of HAp nanorods is also discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1005.5465v1-abstract-full').style.display = 'none'; document.getElementById('1005.5465v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 May, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 figures, one table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1005.4841">arXiv:1005.4841</a> <span> [<a href="https://arxiv.org/pdf/1005.4841">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.82.094418">10.1103/PhysRevB.82.094418 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Strong magneto-elastic coupling and polar properties in orthorhombic Eu1-xYxMnO3 manganite </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Ferreira%2C+W+S">W. S. Ferreira</a>, <a href="/search/cond-mat?searchtype=author&query=Ara%C3%BAjo%2C+J+P">J. P. Ara煤jo</a>, <a href="/search/cond-mat?searchtype=author&query=Pereira%2C+A+M">A. M. Pereira</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Costa%2C+M+M+R">M. M. R. Costa</a>, <a href="/search/cond-mat?searchtype=author&query=Khomchenko%2C+V+A">V. A. Khomchenko</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a>, <a href="/search/cond-mat?searchtype=author&query=Chernyshov%2C+D">D. Chernyshov</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+S+M+F+V+A+P+B">S. M. F. Vilela And P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1005.4841v1-abstract-short" style="display: inline;"> This work reports an experimental investigation of the magneto-elastic coupling and polarization character of magnetic phases of the orthorhombic Eu1-xYxMnO3 system at low temperatures. The temperature dependence of the polarization reversal curves clearly reveals the existence of a reentrant improper ferroelectric phase for x = 0.2 and 0.3. Although a ferroelectric phase is also stable for x = 0.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1005.4841v1-abstract-full').style.display = 'inline'; document.getElementById('1005.4841v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1005.4841v1-abstract-full" style="display: none;"> This work reports an experimental investigation of the magneto-elastic coupling and polarization character of magnetic phases of the orthorhombic Eu1-xYxMnO3 system at low temperatures. The temperature dependence of the polarization reversal curves clearly reveals the existence of a reentrant improper ferroelectric phase for x = 0.2 and 0.3. Although a ferroelectric phase is also stable for x = 0.4, we have no experimental evidence that it vanishing at finite temperatures. From these results and those obtained from other experimental techniques, the corresponding (x,T) phase diagram was traced, yet yielding significant differences with regard to previous reports. An expressive magneto-elastic coupling is revealed by changes observed in both Mn-O bond lengths and Mn-O1-Mn bond angle at the magnetic phase transitions, obtained by temperature dependence of synchrotron x-ray diffraction experiments. Furthermore, signatures of the lattice deformations across the magnetic phase transitions were evidenced by anomalies in the temperature dependence of the lattice mode involving rotations of the MnO6 octahedra. These anomalies confirm the important role of the spin-phonon coupling in these materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1005.4841v1-abstract-full').style.display = 'none'; document.getElementById('1005.4841v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2010. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 Figures, 2 Tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0909.4521">arXiv:0909.4521</a> <span> [<a href="https://arxiv.org/pdf/0909.4521">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0953-8984/21/44/446002">10.1088/0953-8984/21/44/446002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Polar properties of Eu0.6Y0.4MnO3 ceramics and their magnetic field dependence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Ferreira%2C+W+S">W. S. Ferreira</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Kundys%2C+B">B. Kundys</a>, <a href="/search/cond-mat?searchtype=author&query=Ranjith%2C+R">R. Ranjith</a>, <a href="/search/cond-mat?searchtype=author&query=Prellier%2C+W">W. Prellier</a>, <a href="/search/cond-mat?searchtype=author&query=Vilela%2C+S+M+F">S. M. F. Vilela</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0909.4521v1-abstract-short" style="display: inline;"> Eu1-xYxMnO3 exhibits, unlike other magnetoelectric systems, very distinctive features. Its magnetoelectric properties is driven by the magnetic spin of the Mn3+ ion, but they can be drastically changed by varying the content of Y3+, which it does not carry any magnetic moment. Though the x = 0.40 composition has been studied extensively, some basic questions still remain to be thoroughly underst… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4521v1-abstract-full').style.display = 'inline'; document.getElementById('0909.4521v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0909.4521v1-abstract-full" style="display: none;"> Eu1-xYxMnO3 exhibits, unlike other magnetoelectric systems, very distinctive features. Its magnetoelectric properties is driven by the magnetic spin of the Mn3+ ion, but they can be drastically changed by varying the content of Y3+, which it does not carry any magnetic moment. Though the x = 0.40 composition has been studied extensively, some basic questions still remain to be thoroughly understood. Thus, this work is aimed at studying some of its polar properties and their magnetic field dependence as well. The experimental results here reported have shown that this material is very easily polarisable under external electric fields, and so, whenever the polarization is obtained from time integration of the displacement currents, an induced polarization is superposed to the spontaneous one, eventually masking the occurrence of ferroelectricity. We have found clear evidence for the influence of a magnetic field in the polar properties of Eu0.6Y0.4MnO3. The study of electric polarization of Eu0.6Y0.4MnO3 under an external magnetic field yields a value with the same order of magnitude of the remanent polarization determined from polarization reversal experiments. The comparison of the magnetic induced changes on the polarization obtained in polycrystalline samples and single crystals confirms the threshold magnetic field value for the polarization rotation from the a- to the c-direction, and evidencing the importance of the granular nature of the samples in the polar response to magnetic field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0909.4521v1-abstract-full').style.display = 'none'; document.getElementById('0909.4521v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 September, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2009. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">28 pages, 12 figures. Accepted for publication in J. Phys.: Condens. Matter</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0903.5471">arXiv:0903.5471</a> <span> [<a href="https://arxiv.org/pdf/0903.5471">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Re-analysing the phase sequence in Eu0.8Y0.2MnO3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Ferreira%2C+W+S">W. S. Ferreira</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Vilela%2C+S+M+F">S. M. F. Vilela</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0903.5471v1-abstract-short" style="display: inline;"> To clarify the controversy concerning the ferroelectricity of the lower temperature magnetic phases of Eu0.8Y0.2MnO3, hence its multiferroic character, we have studied in detail the temperature dependence of the electric polarization. The existence of a spontaneous polarization in 30K < T < 22K, provides clear evidence for the ferroelectric character of the re-entrant magnetic phase, stable in t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.5471v1-abstract-full').style.display = 'inline'; document.getElementById('0903.5471v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0903.5471v1-abstract-full" style="display: none;"> To clarify the controversy concerning the ferroelectricity of the lower temperature magnetic phases of Eu0.8Y0.2MnO3, hence its multiferroic character, we have studied in detail the temperature dependence of the electric polarization. The existence of a spontaneous polarization in 30K < T < 22K, provides clear evidence for the ferroelectric character of the re-entrant magnetic phase, stable in that temperature range. Both lower temperature magnetic phases allow easily-induced electric polarization, which actually mask any spontaneous polarization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.5471v1-abstract-full').style.display = 'none'; document.getElementById('0903.5471v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 March, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2009. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 4 figures, submitted to Phys. Rev. Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0903.4753">arXiv:0903.4753</a> <span> [<a href="https://arxiv.org/pdf/0903.4753">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Other Condensed Matter">cond-mat.other</span> </div> </div> <p class="title is-5 mathjax"> Coupling between phonons and magnetic excitations in orthorhombic Eu_{1-x}Y_xMnO_3 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Moreira%2C+J+A">J. Agostinho Moreira</a>, <a href="/search/cond-mat?searchtype=author&query=Almeida%2C+A">A. Almeida</a>, <a href="/search/cond-mat?searchtype=author&query=Ferreira%2C+W+S">W. S. Ferreira</a>, <a href="/search/cond-mat?searchtype=author&query=Chaves%2C+M+R">M. R. Chaves</a>, <a href="/search/cond-mat?searchtype=author&query=Kreisel%2C+J">J. Kreisel</a>, <a href="/search/cond-mat?searchtype=author&query=Vilela%2C+S+M+F">S. M. F. Vilela</a>, <a href="/search/cond-mat?searchtype=author&query=Tavares%2C+P+B">P. B. Tavares</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="0903.4753v1-abstract-short" style="display: inline;"> In this work we present a detailed study of the structural and lattice dynamic properties of Y-doped EuMnO3 ceramics (Eu1-xYxMnO3, with 0<x<0.55). A thorough analysis towards the correlation between both structural and Raman modes parameters has been undertaken. Our results provide evidence for two main structural distortions of MnO6 octahedra, arising from a cooperative Jahn-Teller and rotation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.4753v1-abstract-full').style.display = 'inline'; document.getElementById('0903.4753v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0903.4753v1-abstract-full" style="display: none;"> In this work we present a detailed study of the structural and lattice dynamic properties of Y-doped EuMnO3 ceramics (Eu1-xYxMnO3, with 0<x<0.55). A thorough analysis towards the correlation between both structural and Raman modes parameters has been undertaken. Our results provide evidence for two main structural distortions of MnO6 octahedra, arising from a cooperative Jahn-Teller and rotational distortions in these compounds. The temperature dependence of the B1g symmetric stretching mode of the MnO6 units has revealed either a positive or negative shift regarding the pure anharmonic temperature dependence of the phonon frequency, which strongly depends on the Y-concentration. This frequency renormalization is explained in terms of a competition between ferro and antiferromagnetic interactions. The pronounced frequency renormalization of the symmetric stretching mode for x=0.2 evidences the predominance of the ferromagnetic interactions against the antiferromagnetic ones, which is in good correlation with the spontaneous magnetization measured in this compound. The emerging of the shifts referred well above the Neel temperature is likely associated with the coupling between phonons and dynamical fluctuations of the magnetic system, which provides further grounds for the existence of strong spin-phonon coupling in this compound. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0903.4753v1-abstract-full').style.display = 'none'; document.getElementById('0903.4753v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 March, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2009. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, 13 figures, 1 table, submitted to Phys. Rev. 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