Basal plane magnetocrystalline anisotropy and ferromagnetic ordering in TbSc alloys

Abstract

The basal plane anisotropy coefficient K66 has been measured for alloys of composition TbxSc1-x where x=0.89 and 0.825, at temperatures above 77K. The results have been compared with those of Bly (1967) for pure terbium and used in estimating the driving energies Fd to ferromagnetism at the Curie temperatures of the alloys. These are about -0.7K/atom, at least four times as great as for pure terbium, and indicate the extent to which a small scandium content makes the helical phase energetically favourable. The magnitude of Fd at 0K falls below 0.75K/atom when the scandium content reaches 20 at.%, in agreement with the absence of spontaneous ferromagnetic ordering in alloys with greater scandium content.