Magnetostriction and thermal expansion measurements on FeRh1−xPtx alloys

We report high-field magnetostriction and thermal expansion measurements in FeRh1−xPtx (x=0.75, 0.765, and 0.7) compounds. From the thermal expansion measurements we have observed the para-ferromagnetic and ferro-antiferromagnetic transitions for x=0.75 and 0.765, and the para-antiferromagnetic transition in the 0.7 compound. The volume expansion associated with the first-order transitions has been determined. The results of the magnetostriction measurements are complex and are explained here on the basis of an induced transition from an antiferromagnetic to a ferromagnetic state, induced by the applied magnetic field.