Magnetic ordering in pressure-induced phases with giant spin-driven ferroelectricity in multiferroic TbMnO3
| Autor: | Akiko Kikkawa, Hideaki Kitazawa, Noriki Terada, Pascal Manuel, Toyotaka Osakabe, Dmitry D. Khalyavin |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
Condensed matter physics Spins Strongly Correlated Electrons (cond-mat.str-el) Neutron diffraction FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Ferroelectricity Magnetic field Condensed Matter - Strongly Correlated Electrons 0103 physical sciences Antiferromagnetism Multiferroics 010306 general physics 0210 nano-technology Single crystal Critical field |
| Zdroj: | Physical Review B |
| DOI: | 10.48550/arxiv.1903.01319 |
| Popis: | In order to clarify the mechanism associated with pressure/magnetic-field-induced giant ferroelectric polarization in ${\mathrm{TbMnO}}_{3}$, this work investigated changes in magnetic ordering brought about by variations in temperature, magnetic field, and pressure. This was accomplished by means of neutron diffraction analyses under high pressures and high magnetic fields, employing a single crystal. The incommensurate magnetic ordering of a cycloid structure was found to be stable below the reported critical pressure of 4.5 GPa. In contrast, a commensurate $E$-type spin ordering of Mn spins and a noncollinear configuration of Tb spins with $\mathbit{k}=(0,\frac{1}{2},0)$ appeared above 4.5 GPa. The application of a magnetic field along the $a$ axis $({H}_{\ensuremath{\parallel}a})$ under pressure induces a $\mathbit{k}=(0,0,0)$ antiferromagnetic structure in the case of Tb spins above ${H}_{\ensuremath{\parallel}a}$, enhancing the ferroelectric polarization, while the $E$-type ordering of Mn spins is stable even above the critical field. From the present experimental findings, we conclude that the $E$-type ordering of Mn spins induces giant ferroelectric polarization through an exchange striction mechanism. The ${H}_{\ensuremath{\parallel}a}$-induced polarization enhancement can be understood by considering that the polarization, reduced by the polar ordering of Tb moments in a zero field, can be recovered through a field-induced change to nonpolar $\mathbit{k}=(0,0,0)$ ordering at ${H}_{\ensuremath{\parallel}a}\ensuremath{\sim}2$ T. |
| Databáze: | OpenAIRE |
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