Magnetic structure of TbMnO
studied with spherical neutron polarimetry
3次元偏極中性子解析によるTbMnO
の磁気構造
梶本 亮一
; 松田 雅昌; 脇本 秀一
; 武田 全康
; 加倉井 和久; 三井 由佳利*; 吉澤 英樹*
Kajimoto, Ryoichi; Matsuda, Masaaki; Wakimoto, Shuichi; Takeda, Masayasu; Kakurai, Kazuhisa; Mitsui, Yukari*; Yoshizawa, Hideki*
TbMnO
is a typical example of multiferroic compound, where ferroelectric transition takes place accompanied by spin ordering. Spontaneous ferroelectric polarization appears when the spin structure transforms from a sinusoidal structure into a cycloidal spiral structure below
. Interestingly, the amplitude of the spin modulation in the spiral phase is asymmetric, forming an elliptical spiral ordering. Detail of the magnetic structure should be important to understand the mechanism of the ferroelectricity. Accordingly, we have performed spherical neutron polarimetry on a single crystal of TbMnO
using CRYOPAD. By analyzing the polarization of the incident and scattered neutron beam, we were able to obtain detailed information about the magnetic structure including the chirarity of the spiral ordering, the ratio of the major axis and the minor axis of the elliptical spiral, and the angle of the axes of the ellipse relative to the crystalline axes.