Optimization of half-Heusler PtMnSb alloy films for spintronic device applications

Abstract

Half-Heusler PtMnSb alloy films were optimized with varying deposition temperatures on Cr/Ag-buffered MgO(0 0 1) substrates by investigating structural and magnetic properties. Epitaxial growth was achieved in PtMnSb films grown at 200 °C while high magnetization of 530 emu cm−3 was observed at 500 °C. Compared to other Heusler alloys, the PtMnSb films show relatively large anisotropic magnetoresistance ratios with negative sign, which could be attributed to high spin–orbit interaction in the PtMnSb films owing to Pt. Furthermore, current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices as a kind of representative spintronic devices were fabricated with the structure of PtMnSb/Ag/PtMnSb. Room-temperature CPP-GMR effect was first observed in the PtMnSb-based CPP-GMR devices.