High thermal stability of perpendicular magnetic anisotropy in the MgO/CoFeB/W thin films

Autor: Hongxin Yang, Lilin Wang, Y.Q. Guo, C.Q. Hu, Yongxia Zhao, S.G. Wang, S.P. Shen, Y. Gao, C.L. He, Tao Zhu, Qirui Cui, X.Z. Zhan, H. Bai
Rok vydání: 2021
Předmět:
Zdroj: Applied Surface Science. 568:150857
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2021.150857
Popis: Perpendicular magnetic anisotropy (PMA) with high thermal stability is greatly essential for ultrahigh density and stable data storage devices. Here, the effect of vacuum annealing on PMA of MgO/CoFeB/W stacks was investigated. It was shown that the PMA can be well maintained after annealing at 590 °C, which is much higher than that in traditional Ta-based PMA films. Using the polarized neutron reflectometry, the Co-Fe atoms proportion of the CoFeB/W interface was deliberately determined at different temperatures. It is found that the Co and Fe atoms of CoFeB/W interface had strongly segregation after annealing at 590 °C Furthermore, the effect of different proportion of Co-Fe elements on the PMA was systematically studied by the first-principles calculation. Our first-principles calculation and further analysis reveal that different Co-Fe proportion leads to the modification of orbital hybridization between d xy and d x 2 - y 2 orbitals at the CoFe/W interface, indicating that the interfacial segregation can enhance the PMA. These findings unveil the origin of PMA in W-based devices with high thermal stability and can promote their future industrial applications.
Databáze: OpenAIRE