Compositional Effects on the Structure and Phase Transition of Epitaxial FeRh Thin Films

Compositional and temperature dependent ferromagnetic/anti-ferromagnetic transition of highly textured Fe_{100 - x}Rh_x (where x = 35 to 65) thin films deposited epitaxially on MgO (001) single crystal substrates were studied. First-order transition from ferromagnetic to anti-ferromagnetic phase was observed around 48 at. % Rh where x-ray diffraction spectra revealed a sharp discontinued decrease in lattice parameter-c coupled with a sudden decrease in magnetization from 1600 to 200 emu/cm³. The transition was sharp compared to non-textured randomly oriented thin films, bearing similarities to bulk FeRh. Temperature-dependent x-ray diffraction spectra and magnetic measurements revealed the occurrence of temperature induced anti-ferromagnetic to ferromagnetic phase transitions for films with Rh content larger than 47 at. %. The temperatures at which such transitions occurred were dependent on the Rh content, and broadened with increasing amounts of Rh.