Effect of oxidation on perpendicular magnetic behavior of MnBi thin films

• Published in: Journal of alloys and compounds Vol. 672; pp. 59 - 63
• Main Authors: Sun, M.Y., Xu, X.W., Liang, X.A., Sun, X.W., Zheng, Y.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-07-2016
• Subjects: Coercive force; Expansion; Exposure; Grain boundaries; Magnetic properties; Magnetization; MnBi thin film; Oxidation; Oxidation effect; Perpendicular magnetic anisotropy; Thin films; Perpendicular magnetic anisotropy; MnBi thin film; Oxidation effect
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.01.240

Low-temperature-phase (LTP) MnBi thin films with perpendicular magnetization were fabricated. The influence of oxidation on magnetic properties was investigated for samples experiencing the 14-day exposure to air. The saturation magnetization Ms of MnBi thin film was reduced by 35% while its coercivity Hc was enlarged by 23% due to oxidation. The precipitation of crystalline bismuth was observed in MnBi after exposure to air for 14 days. The reduction of Ms is thought to be due to the decomposition of MnBi as a result of the oxidation of Mn, while the enlarged Hc is deduced to be caused by the weakened inter-grain exchange energy at grain boundaries. Almost no changes in structural and magnetic properties were observed in the MnBi thin film protected with a Ta capping layer even after prolonged exposure to air.
•LTP MnBi thin films with perpendicular magnetization were fabricated.•Obvious oxidation effect on MnBi films was observed and systematically analyzed.•The effect on magnetic performance was strictly controlled by surface protection.