Tuning the magnetic properties and surface morphology of D0_(22) Mn_(3-δ)Ga films with high perpendicular magnetic anisotropy by N doping

摘要

We report the tunable magnetic properties and the smoothened surface morphology of epitaxial D0_(22) Mn-Ga (Mn_3Ga and Mn_(2.5)Ga) films by N doping using reactive sputtering at 480 ℃. The 50 nm thick Mn-Ga films grown with the N_2/Ar gas flow rate (η) up to 0.66% showed 33%-50% reduction in the saturation magnetization compared to non-doped Mn-Ga. In particular, a single D0_(22) phase was obtained in an optimal η range for Mn_(2.5)Ga, resulted in the perpendicular magnetic anisotropy energy density of ～1 MJ/m~3 with 33% reduction in magnetization. Furthermore, the introduction of N provided the smoothened surface morphology at 50 nm thickness despite its high growth temperature, which is advantageous for thin film device applications.