Investigation of perpendicular magnetic anisotropy in CoFeMnSi based heterostructures

Abstract

In this work, perpendicular magnetic anisotropy (PMA) is realized in MgAl2O4(MAO)/CoFeMnSi(CFMS)/MgAl2O4/Ti heterostructures annealed at 300 °C and 400 °C. We show that interfacial PMA is very responsive to the annealing temperature and the CFMS layer thickness (tCFMS). A large PMA is achieved for tCFMS = 2.0 nm. An improvement in the out-of-plane saturation magnetization (Ms⊥) with PMA is found to get remarkably stimulated by the bottom MgAl2O4/CFMS interface. Besides, a uniaxial PMA is observed for an as-deposited stack with tCFMS ≤ 1.5 nm. Annealing at 400 °C significantly promoted adequate interfacial oxidation with the improved thermal stability of the heterostructure. Through X-ray photoelectron spectroscopy (XPS), the formation of Co–O bonds occurring as a result of the hybridization of Co-3dZ2 and O-2pZ orbitals at the interface shared by CFMS with MAO is identified as the microscopic origin of the observed PMA in these stacks. These findings indicate that the CFMS and MAO-based structures have immense potential for the next generation spintronic devices.