Temperature Dependence of Magnetic Anisotropy in MnAlGe

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 K 1 . The saturation moment and K 1 extrapolated to 0 K are 1.70 µ B /Mn and 9.7×10 6 erg/cc, respectively. The observed temperature dependence of K 1 , after corrected for dipole-dipole interaction energy, is expressed in terms of the saturation magnetization σ as 10.7×10 6 [σ( T )/σ(0)] 3.08 erg/cc, in good agreement with the spin wave theory which predicts the exponent 3.