Phase diagram for spin glasses with uniaxial anisotropy

A model of spin glasses containing single-ion uniaxial anisotropy is solved within (replica-symmetric) mean-field theory. For small anisotropy strength D, two phase transitions are predicted as the temperature is reduced. The first transition involves the freezing of the spin component(s) corresponding to the easy axis (axes). At the second transition the remaining spin components freeze. For sufficiently large mod D mod , only the first of these transitions occurs.