Magnetic Phase Diagram of Competing Antiferromagnet Au–Cr

Abstract

The magnetic phase diagram of an fcc alloy AuCr has been constructed by means of magnetic and neutron diffraction measurements. It shows a nature of spin glass at dilute concentration of Cr and a nature of a long range antiferromagnetism at high concentration. At intermediate concentration, about 11 to 13 at.% Cr, it has short range antiferromagnetic clusters. Since the cluster size is almost independent of temperature change below the freezing temperature of spins which is determined by the susceptibility measurement, we can conclude that the intermediate phase is composed of antiferromagnetic clusters frozen in the matrix of spin glass. Near 13 at.%Cr, the system has narrow region which shows the reentrant property.