MEAN-FIELD THEORY OF THE ISING RANDOM-ANISOTROPY-AXIS MODEL IN THE LARGE-COMPONENT LIMIT

The Ising random-anisotropy-axis model with additional noncubic anisot ropy is investigated in mean-field theory in the limit p --> infinity for p-component random vectors on a lattice of N sites. The effects of anisotropy for statistically independent and identically distributed random-vector components with a trimodal probability distribution are studied in the limits alpha = p/N = 0 and alpha > 0. Ferromagnetic, mi xed, and residual ordered phases are found in the first case, while on ly mixed ordered and spin-glass phases are found for the latter. Phase diagrams with explicit phase boundaries are obtained.