Giant interfacial perpendicular magnetic anisotropy in MgO/CoFe/capping layer structures
Giant interfacial perpendicular magnetic anisotropy in MgO/CoFe/capping layer structures
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DOI：
10.1063/1.4976517
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发表时间：
2017-02-13
影响因子：
4
通讯作者：
Wang, Kang L.
中科院分区：
文献类型：
--
作者：
Peng, Shouzhong;Zhao, Weisheng;Wang, Kang L.
基于CoFeB/MgO/CoFeB结构的磁性隧道结由于其在自旋转移矩磁随机存取存储器（STT - MRAM）中的应用而备受关注。为了实现高热稳定性，需要较大的界面垂直磁各向异性（PMA）。在此，我们使用第一性原理计算来研究MgO/CoFe/覆盖层结构的磁各向异性能（MAE），其中覆盖材料包括5d金属Hf、Ta、Re、Os、Ir、Pt和Au以及6p金属Tl、Pb和Bi。我们证明了通过使用合适的覆盖材料来增强PMA是可行的。在具有Hf、Ta、Os、Ir和Pb覆盖材料的结构中发现了相对较大的PMA。更重要的是，MgO/CoFe/Bi结构产生了巨大的PMA（6.09 mJ/m²），大约是MgO/CoFe/Ta结构的三倍。通过检查每个原子层和轨道对MAE的贡献，阐明了MAE的起源。这些发现提供了对PMA的全面理解，并指出了实现具有高热稳定性的先进节点STT - MRAM的可能性。由AIP出版公司出版。
Magnetic tunnel junction based on the CoFeB/MgO/CoFeB structures is of great interest due to its application in the spin-transfer-torque magnetic random access memory (STT-MRAM). Large interfacial perpendicular magnetic anisotropy (PMA) is required to achieve high thermal stability. Here, we use the first-principles calculations to investigate the magnetic anisotropy energy (MAE) of the MgO/CoFe/capping layer structures, where the capping materials include 5d metals Hf, Ta, Re, Os, Ir, Pt, and Au and 6p metals Tl, Pb, and Bi. We demonstrate that it is feasible to enhance PMA by using proper capping materials. Relatively large PMA is found in the structures with the capping materials of Hf, Ta, Os, Ir, and Pb. More importantly, the MgO/CoFe/Bi structure gives rise to giant PMA (6.09 mJ/m(2)), which is about three times larger than that of the MgO/CoFe/Ta structure. The origin of the MAE is elucidated by examining the contributions to MAE from each atomic layer and orbital. These findings provide a comprehensive understanding of the PMA and point towards the possibility to achieve the advanced-node STT-MRAM with high thermal stability. Published by AIP Publishing.