Temperature Dependence of Magnetic Anisotropy in MnAlGe

Abstract

Magnetization measurements were made on a single crystal of ferromagnetic MnAlGe from 4.2 K to 350 K in order to determine the uniaxial magnetic anisotropy constant K₁. The saturation moment and K₁ extrapolated to 0 K are 1.70 μ_B/Mn and 9.7×10⁶ erg/cc, respectively. The observed temperature dependence of K₁, after corrected for dipole-dipole interaction energy, is expressed in terms of the saturation magnetization σ as 10.7×10⁶[σ(T)⁄σ(0)]^3.08 erg/cc, in good agreement with the spin wave theory which predicts the exponent 3.