Relationship between magnetocrystalline anisotropy, including second-order contribution, and initial magnetic permeability for monocrystalline MnZn ferrous ferrite

Abstract

For monocrystalline MnZn ferrous ferrite the magnetocrystalline anisotropy constants K₁ and K₂, the initial permeability μ_i, and the saturation magnetization M_s have been measured in considerable detail as functions of temperature T. The effect of K₂ has been incorporated in the commonly used expressions describing the dependence on K₁ and M_s of μ_i due to rotation of magnetization and displacement of domain walls. It is shown that a nonzero K₂ can limit considerably the secondary maximum of μ_i(T) at the temperature of anisotropy compensation. The results of measurements on monocrystalline Mn_0.42Zn_0.44Fe_2.145O₄ are interpreted with the aid of the theoretical expressions obtained for μ_i as a function of K₁, K₂, and M_s. Special attention has been paid to the temperature range around the secondary maximum of μ_i(T) at −82 °C and the temperature range around the primary maximum of μ_i(T) close to the Curie temperature.