A Role of the magnetic chirality in polarization flip in YMnO

YMnOに見られる誘電分極反転における磁気カイラリティの寄与

脇本 秀一  ; 木村 宏之*; 福永 守*; 坂本 勇馬*; 武田 全康  ; 加倉井 和久; 野田 幸男*

Wakimoto, Shuichi; Kimura, Hiroyuki*; Fukunaga, Mamoru*; Sakamoto, Yuma*; Takeda, Masayasu; Kakurai, Kazuhisa; Noda, Yukio*

A multiferroic compound YMnO shows characteristic dielectric polarization flip upon the magnetic phase transition from commensurate magnetic (CM) to low-temperature incommensurate magnetic (LTICM) phases. By utilizing simultaneous measurements of dielectric polarization and magnetic chirality by polarized neutron diffraction, we have studied the direct relation between them. We have identified that and , two major mechanisms of spin-driven ferroelectricity, are dominant in the CM and LTICM phases, respectively, and concluded that a conservation of magnetic chirality gives rise to the polarization flip upon the CN-LTICM transition.