Temperature dependence of the magnetocrystalline anisotropy energy of terbium in the basal plane

Abstract

The basal plane magnetocrystalline anisotropy energy of terbium has been measured in the temperature range 17.4 to 201K in magnetic fields in the range 2 to 4 using a rotating sample magnetometer. The data has been analysed by three different methods, with special attention being given to the necessary corrections due to the non-collinearity of M and B, and the three methods are shown to produce equivalent results. The values of K₆⁶ obtained are in good agreement with existing data above 50K but are much bigger below this temperature. The data is also in good agreement with the single-ion crystal field theory of Callen and Callen (1966), despite tha fact that the anisotropy is thought to be principally of magnetoelastic origin. K₁₂¹² has been shown to be negligible in comparison with K₆⁶.