Room-temperature ferromagnetic semiconductor Fe-doped β-Ga ₂ O ₃ thin films with high saturation magnetization and low coercivity

Emergent ferromagnetism in β-Ga₂O₃ with an ultra-wide bandwidth and high electrical breakdown strength offers exciting opportunities for fabricating robust spintronic devices. One pertinent obstacle in the material has been the low saturation magnetization, which precludes its practical application in magnetic devices. In this work, large-scale Fe-doped β-Ga₂O₃ diluted magnetic semiconductor (DMS) films are synthesized using a polymer-assisted deposition method, and the effect of Fe doping on their structural and magnetic properties is investigated. Remarkably, the optimal sample exhibits a high saturation magnetization (70 emu cm^-3 at 300 K), much larger than those in previously reported stable oxide DMS films, as well as a low coercivity (12 Oe at 300 K). Further analysis shows that our samples manifest a typical bound magnetic polaron (BMP) model and the high saturation magnetization originates from the strong ferromagnetic coupling between the BMPs which is enhanced by Ga vacancies. The Fe-doped β-Ga₂O₃ thin films with high saturation magnetization and low coercivity may provide a promising platform for related semiconductor spintronics.