The random anisotropy axis model in the infinite-range limit

Abstract
The authors study the thermodynamic properties of the random-anisotropy-axis model of amorphous magnets when the interaction range becomes infinite. This model is exactly soluble and has a ferromagnetic second-order phase transition at the same temperature as the pure n component spin system. There is no spin glass phase and mean-field theory is rigorously justified in this case. Explicit expressions are given for the magnetisation, specific heat and susceptibility near the transition and at low temperature, in the limit of strong anisotropy.