The Role of Clustering for Antiferromagnetic Phase Transitions in \gamma--{\rm Mn} Alloys

Abstract

\gamma--Mn alloys show a wealth of antiferromagnetic phase transitions as a function of alloy concentration. The experiments show that the impurities sometimes cluster and sometimes anti--cluster. In this study, we show that the clustering plays an important role for the first order antiferromagnetic phase transition. Although we mainly consider the two dimensional square lattice, the model can explain some of the phase transition in \gamma--Mn alloys as well.