Competing order parameters in quenched random alloys: Fe1-xCoxCl2

A study is reported of the magnetic properties of the random alloy Fe1-xCoxCl2, which represents an archetypal example of a system with competing orthogonal spin anisotropies. Behavior similar to previous experiments and theoretical predictions is found, but with important qualitative and quantitative differences; in particular the phase transition in one variable is drastically altered by the existence of long-range order in the other variable. It is hypothesized that this is due to microscopic random-field effects. © 1980 The American Physical Society.