We use torque measurements to determine the field dependence of the spin-glass freezing temperature in $\mathrm{Cu}\mathrm{Mn}$ alloys doped with gold impurities. We find that by increasing the concentration of gold, and thus enhancing the random anisotropy forces, the transition line changes from Gabay-Toulouse-like to de Almeida-Thouless-like. This change to an Ising behavior is an agreement with the predictions of the mean-field model of Kotliar and Sompolinsky for a Sherrington-Kirkpatrick spin glass with random anisotropy.

• Received 3 July 1984

DOI:https://doi.org/10.1103/PhysRevB.30.6791