Magnetization and Anisotropy in Gallium Iron Oxide

Abstract

The magnitude and direction of the magnetization (M) of a single crystal of orthorhombic Ga2−xFexO3(x≈1.08) were measured separately in a magnetic field (H) which was applied in various crystallographic directions and ranged up to 23 kOe in magnitude. Temperatures (T) between 77° and 300°K were used. The apparatus included a vibrating sample magnetometer equipped with two mutually orthogonal pairs of pickup coils mounted on a rotating base. Analyses of the data show that M depends on H as well as on H/H, and that the uniaxial anisotropy coefficients (K) are such that the ratios KA/M2A and KB/M2B, which refer to the ac and bc planes, respectively, are independent of H within experimental error (<4%) and independent of H/H within experimental error (∼20%). The analyses show, moreover, that these ratios increase monotonically with increasing T, and that KA and KB, when extrapolated to H=0, are linear functions of T between 110° and 295°K. At 77°K, the values of KA and KB are determined to be 2.43×106 erg/cm3 and 4.37×106 erg/cm3, respectively.