Magnetostriction of Dilute Tb Ions in Several Metallic Matrices

Abstract

The paramagnetic magnetostriction (MS) of dilute Rare Earth (RE) ions in metals is somewhat larger than 10⁻³ per RE cell ^1,2,3 comparable to the socalled giant MS of the magnetically ordered RE elements. Thus giant MS is very much a single ion effect and seems to depend mainly on the size and direction of the static component of the ionic magnetic moment in the crystal, independent of whether this component came about by internal or external fields. The source of the effect is the asphericity of the charge distribution of the ground state of the 4f shell, which is present when L ≠ 0, and whose axis is carried along with that of the magnetic moment through strong spin orbit coupling. It is, however, very difficult to achieve quantitative understanding of the distortion of the crystal under the action of this asphericity, since the distortion depends sensitively on the charge distribution of the conduction and valence electrons and on their polarizability.