A Theory of the Magnetovolume Effect at Finite Temperatures

The Liberman-Pettifor virial theorem is extended to the finite temperatures, and the expressions for the spontaneous volume magnetostriction and the electronic contribution to the thermal expansion coefficient are given by using the functional integral method within the static approximation. The temperature variations of these quantities are determined mainly by the amplitude of the local magnetic moment and the s-d charge transfer. Two types of the thermal expansion, the αFe type and the Weiss model type, appear within the CPA-LSA and their properties are examined and discussed.