Yu-Pu Wang et al 2014 J. Phys. D: Appl. Phys. 47 495002
Abstract:
Perpendicular magnetic anisotropy (PMA) was achieved in annealed Fe2Cr1-xCoxSi (FCCS) Heusler alloys with different Co composition x. The Co composition is varied to tune the Fermi level in order to achieve both higher spin polarization and better thermal stability. The PMA is thermally stable up to 400oC for FCCS with x = 0, 0.3, 0.5, and 350oC for FCCS with x = 0.7, 0.9, 1. The thickness of FCCS films with PMA ranges from 0.6 nm to 1.2 nm. The annealing temperature and FCCS thickness are found to greatly affect the PMA. The magnetic anisotropy energy density KU is 2.8 × 106 erg/cm3 for 0.8 nm Fe2CrSi, and decreases as Co composition x increases, suggesting that the PMA induced at FCCS/MgO interface is dominated by the contribution of Fe atoms. There is a trade-off between high spin polarization and strong PMA by adjusting Co composition.