Spin-Glass and Ferromagnetic Behavior Induced by Random Uniaxial Anisotropy

The effect of a random uniaxial anisotropy axis on the magnetic properties of an amorphous ferromagnet is considered. It is found that in a quenched system random anisotropy with an isotropic angular distribution destroys the ferromagnetic state in fewer than four dimensions. The low-temperature phase is, instead, an Edwards-Anderson spin-glass. In more than four dimensions ferromagnetism or spin-glass ordering is found depending on the degree of disorder. Some properties of the ferromagnetic state are outlined.