Anisotropic physical properties of the charge and orbital ordering phase in [formula omitted

Abstract

Anisotropic properties of a single-domain crystal Bi 1 - x Sr x MnO 3 with x = 0.47 were investigated. Temperature dependence of resistivity and magnetization show an anomaly which is accompanied by a hysteresis at 400 – 550 K and a kink near 600 K. The hysteresis and the kink may be attributed to the charge order–disorder transition accompanied with orbital commensurate–incommensurate phenomenon, and to the orbital order–disorder transition, respectively. Magnetization measurements show an antiferromagnetic transition near 150 K. Below 150 K, the magnetization for a magnetic field in the ab-plane is larger than that along the c -axis. This magnetic anisotropy indicates that the Mn spin moments direct to the c -axis. In the charge ordering phase, anisotropy of the resistivity is approximately ρ ab / ρ c ≃ 10 . This indicates that e g electrons on excess Mn 3 + ions can move more easily along the c -axis than in ab-plane.