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

Abstract

Compositional and temperature dependent ferromagnetic/anti-ferromagnetic transition of highly textured Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">100 - x</sub> Rh <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> (where <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> = 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- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> coupled with a sudden decrease in magnetization from 1600 to 200 emu/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . 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.