Magnetostriction in TbFe 2: weak influence of the internal structural distortion

Abstract

The magnetostriction coefficients λ 1 1 1 and λ 1 0 0 of the Laves phase TbFe 2 are calculated by the ab initio electron theory in local-density approximation with constraints for the 4f states and by the full-potential linear–muffin–tin–orbital method. It is shown that the aspherical 4f charge density may produce large magnetostrictive strains. A large magnetostriction anisotropy is found ( λ 1 1 1 ⪢λ 1 0 0 ) which arises from the intrinsic electronic structure, whereas the coupling of the magnetostrictive strain to an internal structural distortion of the unit cell, suggested formerly by Cullen and Clark, turns out be be of minor importance.