Effects of atomic ordering on the Curie temperature of FePd L1 type alloys

Abstract

In this work, we systematically studied the effects of atomic ordering on the Curie temperature of FePd alloys in the composition region of L10 phase. The Curie temperatures of the bulk Fe–50 at. % Pd, Fe–55 at. % Pd, Fe–60 at. % Pd alloys for both ordered and disordered structures have been measured. Unlike the Curie temperatures reported in the literature, atomic ordering decreases the Curie temperature by about 30 K for each of the compositions. Using a molecular field model, we calculated the Curie temperatures of Fe–Pd alloys. The simulation results show that the difference of the Curie temperature of the disordered and ordered states arises from the change of the nearest-neighbor occupation probabilities and the change of atomic interactions.