2006-7

Reversal of Ferroelectric Polarization in TbMnO₃ Induced by Rotation of Magnetic Field Direction

磁場方位回転によるTbMnO₃の強誘電分極の反転

TbMnO₃ with an orthorhombically distorted perovskite structure shows gigantic magnetoelectric effects originating from the ferroelectricity induced by magnetic order. We have investigated the change in its electric polarization with sweeping magnetic field along various paths. With sweeping a magnetic field from +9 T to -9 T, the direction of electric polarization returns to the initial state after 90-digree flopping twice. In contract, the electric polarization is reversed by the rotation of a magnetic field by 180 degrees around the c-axis.

IMRAM, Tohoku University: N. Abe, K. Taniguchi, T. Arima
IMR, Tohoku University: Y. Iwasa

Reference: N. Abe, K. Taniguchi, S. Otani, T. Takenobu, Y. Iwasa, and T. Arima,
“Polarization reversal in multiferroic TbMnO₃ with rotating magnetic-field direction”, in preparation.

斜方晶TbMnO₃では磁気秩序が強誘電分極を誘発するため，巨大な電気磁気効果を示すことが知られている．この物質の電気分極が磁場掃引経路によってどのように変化するのかを調べた．磁場方向をb軸方向に固定して9Tから-9Tまで掃引すると，電気分極は二度の90度回転の後初めの向きに戻るが，磁場強度を9Tに固定したまま磁場方位をab面内で+bから-bまで180度回転させた場合は，分極が反転することがわかった．

東北大学多元物質科学研究所：阿部伸行，谷口耕治，有馬孝尚
東北大学金属材料研究所：岩佐義宏