MAGNETOSTRICTION OF AMORPHOUS GDXAG1-X ALLOYS

Magnetostriction measurements above 4. 2 K and up to 2. 2 T have been performed in the amorphous alloys Gd//xAg//1// minus //x (0. 30 less than equivalent to x less than equivalent to 0. 40). Magnetostriction is purely of volume character. It shows with composition a maximum at x equals 0. 35, and this behavior can be explained if forced volume magnetostriction derives from the strain dependence of the two-ion longitudinal spin correlation. The isotropic spin exchange correlation seems irrelevant in these series, as also put forward by thermal expansion measurements.