Neutron diffraction studies on the multiferroic conical magnet Ba2Mg2Fe12O22

作者：Ishiwata Shintaro^*; Okuyama Daisuke; Kakurai Kazuhisa; Nishi Masakazu; Taguchi Yasujiro; Tokura Yoshinori

来源：Physical Review B, 2010, 81(17): 174418.

DOI：10.1103/PhysRevB.81.174418

Magnetic structure of a multiferroic Y-type hexaferrite Ba2Mg2Fe12O22 with helical-spin structures propagating along [001] below 195 K has been extensively studied, using polarized and unpolarized neutron diffractions under transverse magnetic fields B (perpendicular to[001]) up to 4.5 T. At zero magnetic field, a longitudinal-conical spin state was found to emerge below about 50 K, which enables the low-B control of electric polarization P. The magnetic phase diagram was investigated as a function of transverse B and coexistence of several phases with different helical-spin periodicity was confirmed at low-B region. Furthermore, by using the polarized neutron diffraction under transverse B, we verified that the ferroelectric phase with the largest P value with a commensurate k(0) vector of (0, 0, 3/2) has a transverse-conical spin structure, in which the spin component perpendicular to B shows every 90 degrees rotation with translation along the k(0) direction. The relation between the transverse-conical spin structure and P as a function of the transverse B was discussed in terms of the inverse Dzyaloshinskii-Moriya model.

• 出版日期2010-5-1