Single ion model for magnetostriction in rare-earth–transition-metal amorphous films

Abstract

The mechanism of magnetostriction in rare-earth–transition-metal amorphous films was investigated based on a single ion anisotropy model for rare-earth atoms using a point charge approximation. The theory was compared with the observed magnetostriction in (Gd0.75R0.25)19Co81 films with various rare-earth elements R. The dependence of the observed magnetostriction on substitutional rare-earth elements R is well explained with this model. Screening of an electric field was found to be essential for magnetostriction, and a screening function was determined from the observed magnetostriction. The screening was found to be of the type in which an electric field decreases more rapidly with an increase of distance than a Coulombic interaction.