Evidence of magnetic anisotropy and spin-reorientation in the textured MnBi crystal

¹ Department of Physics, Shanghai University of Electric Power - Shanghai 200090, China
² Department of Physics, Shanghai University - Shanghai 200444, China
³ Department of Materials Science and Engineering, Shanghai University - Shanghai 200444, China
⁴ Key Laboratory of Advanced Civil Engineering Materials (Tongji University), Ministry of Education - Shanghai 200092, China

^a ysliu@shiep.edu.cn

Received: 16 May 2011
Accepted: 5 September 2011

Abstract

Magnetic anisotropy is investigated systematically for the textured MnBi crystal. The magnetic anisotropy exists in magnetization behaviors, hysteresis loops, and remnant magnetization. An abnormal coercivity field H_c is found in the textured MnBi: H_c perpendicular to the c-axis is larger than that parallel to the c-axis. The mechanism of anisotropy is discussed based on magnetocrystalline anisotropy in MnBi. The behavior of a.c. susceptibility has similar trends with frequency variation, not displaying a spin-disorder characteristic. The MnBi with ferromagnetic order has a higher loss under high frequencies than under low frequencies. Some spin-reorientation evidence in the MnBi is also obtained.