Unusual Elastic Properties of Gadolinium and Invar

Abstract

In order to investigate the anomalous elastic properties relating to the large volume magnetostriction, Young’s and shear moduli of Gd and Invar were measured as a function of temperature and magnetic field. Their bulk moduli were calculated from the measured values. In spite of the fact that the thermoelastic coefficients of the measured moduli were negative for Gd and positive for Invar, the coefficient of the bulk modulus was negative for each of the two, and an analogous strong magnetic effect on the calculated moduli was observed even for magnetically saturated states. The data for Gd are discussed on the basis of the RKKY interaction.