Magnetic Properties of bcc FeRh1-xMx Systems

The magnetic properties of ordered bcc FeRh1-xMx alloys (M=Fe, Co, Ni, Pd, Ir and Pt) were studied, in terms of correlations among the antiferromagnetic-ferromagnetic transition temperature T0, Curie temperature, magnetization, and lattice constant. Substitution of the 3d element M for Rh diminishes the transition temperature T0, since the large magnetic moment of the M atom stabilizes the ferromagnetism. Moreover, a first-order antiferromagnetic-paramagnetic transition was observed in an FeRh1-xIrx system. The mechanism of such first-order phase transitions can be explained phenomenologically by introducing magneto-volume coupling into a model based on the SCR theory. The ground state properties of FeRh and FeRh1-xPdx are well explained by first-principle band calculations based on the linearized muffin-tin orbital method.