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Magnetic-Field and External-Pressure Effect on Ferroelectricity in Manganites: Comparison between GdMnO$_{3}$ and TbMnO$_{3}$

K. Noda·S. Nakamura·J. Nagayama·H. Kuwahara
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Abstract

We have investigated dielectric properties in Mott insulators GdMnO$_{3}$ and TbMnO$_{3}$ under magnetic fields and external quasihydrostatic pressures. In the case of GdMnO$_{3}$, thermal hysteresis for dielectric constant $ε$ and discontinuous lattice distortion were observed at ferroelectric transition temperature ($T_{C}$), and ferroelectric spontaneous polarization was suppressed by application of external pressure. These results indicate that the ferroelectric transition in GdMnO$_{3}$ is a first-order displacive-type one. On the other hand, the thermal hysteresis and discontinuous lattice striction were not observed at $T_{C}$ in TbMnO$_{3}$. The peak of $ε$ corresponding to ferroelectric transition was shifted toward higher temperatures by application of external pressure in TbMnO$_{3}$. The ferroelectric transition of TbMnO$_{3}$ was thought to be a second-order order-disorder-type one.

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K. Noda, S. Nakamura, J. Nagayama, H. Kuwahara. 2004-12-07. Magnetic-Field and External-Pressure Effect on Ferroelectricity in Manganites: Comparison between GdMnO$_{3}$ and TbMnO$_{3}$. https://doi.org/10.1063/1.1851420

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