Unveiling the role of Co-O-Mg bond in magnetic anisotropy of Pt / Co / MgO using atomically controlled deposition and in situ electrical measurement
Unveiling the role of Co-O-Mg bond in magnetic anisotropy of Pt / Co / MgO using atomically controlled deposition and in situ electrical measurement
复制标题
利用原子控制沉积和原位电测量揭示 Co-O-Mg 键在 Pt / Co / MgO 磁各向异性中的作用
DOI：
10.1103/physrevb.95.094417
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发表时间：
2017
影响因子：
3.7
通讯作者：
Yihong Wu
中科院分区：
文献类型：
--
作者：
Yumeng Yang;Jiaren Yuan;Long Qi;Ying Wang;Yanjun Xu;Xiaowei Wang;Y. Feng;Baoxi Xu;Lei Shen;Yihong Wu
尽管界面垂直磁各向异性在Co（Fe）/MgO基磁性隧道结中起着至关重要的作用，但其内在机制仍存在争议。在这里，我们报告了一个解剖研究的氧和镁的影响$\mathrm{Pt}/\mathrm{Co}$双层通过反复原位异常霍尔效应测量，控制氧气暴露，镁沉积在一个可调真空系统。我们发现，化学吸附的氧不仅淬灭的有效磁矩的Co表面层，但也软化其磁各向异性。然而，随后对预先暴露于氧气的$\mathrm{Pt}/\mathrm{Co}$表面进行镁除尘可以恢复磁各向异性。对费米能级附近的交换分裂和轨道杂化的从头计算给出了一个清晰的物理解释。研究结果表明，Co（Fe）-O-$M$键在实现Co（Fe）/MgO异质结构界面垂直磁各向异性中起着比Co（Fe）-O键更重要的作用.
Despite the crucial role of interfacial perpendicular magnetic anisotropy in a Co(Fe)/MgO-based magnetic tunnel junction, the underlying mechanism is still being debated. Here, we report an anatomical study of the oxygen and Mg effect on $\mathrm{Pt}/\mathrm{Co}$ bilayers through repeated in situ anomalous Hall effect measurements, controlled oxygen exposure, and Mg deposition in an ultrahigh vacuum system. We found that chemisorbed oxygen not only quenches the effective magnetic moment of the Co surface layer, but also softens its magnetic anisotropy. However, a subsequent Mg dusting on the oxygen preexposed $\mathrm{Pt}/\mathrm{Co}$ surface can recover the magnetic anisotropy. The ab initio calculations on the exchange splitting and orbital hybridization near the Fermi level give a clear physical explanation of the experimental observations. Our results suggest that the Co(Fe)-O-$M$ bond plays a more important role than the widely perceived Co(Fe)-O bond does in realizing interfacial perpendicular magnetic anisotropy in Co(Fe)/MgO heterostructures.