Artificially engineered Heusler ferrimagnetic superlattice exhibiting perpendicular magnetic anisotropy

Abstract

To extend density limits in magnetic recording industry, two separate strategies were developed to build the storage bit in last decade, introduction of perpendicular magnetic anisotropy (PMA) and adoption of ferrimagnetism/antiferromagnetism. Meanwhile, these properties significantly improve device performance, such as reducing spin-transfer torque energy consumption and decreasing signal-amplitude-loss. However, materials combining PMA and antiferromagnetism rather than transition-metal/rare-earth system were rarely developed. Here, we develop a new type of ferrimagnetic superlattice exhibiting PMA based on abundant Heusler alloy families. The superlattice is formed by [MnGa/Co 2 FeAl] unit with their magnetizations antiparallel aligned. The effective anisotropy (K u eff) over 6 Merg/cm 3 is obtained, and the SL can be easily built on various substrates with flexible lattice constants. The coercive force, saturation magnetization and K u eff of SLs are highly controllable by varying the thickness of MnGa and Co 2 FeAl layers. The SLs will supply a new choice for magnetic recording and spintronics memory application such as magnetic random access memory.