Degenerate magnetic structures and antiferromagnetic phase transitions in $gamma$-Mn alloys

Abstract

Manganese alloy systems, which have been studied experimentally, show a host of antiferromagnetic phase transitions. Developing a linearized theory for the clas¬sical Heisenberg model, we can solve the local distortion of model of spins around an impurity in non-collinear antiferromagnet. Since the alloying removes the degeneracy in non-collinear magnets, this theory is useful. Looking at the case of $gamma$-Mn alloys, especially $Mn_3 Pt$, we can predict the experimentally observed phase transitions caused by alloying.