Perpendicular magnetic anisotropy at the Fe/MgAl2O4 interface: Comparative first-principles study with Fe/MgO
Perpendicular magnetic anisotropy at the Fe/MgAl2O4 interface: Comparative first-principles study with Fe/MgO
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DOI：
10.1103/physrevb.98.224421
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发表时间：
2018-03
影响因子：
3.7
通讯作者：
K. Masuda;Y. Miura
中科院分区：
文献类型：
--
作者：
K. Masuda;Y. Miura
本文对Fe/MgAl$_2$O$_4$的界面磁晶各向异性进行了理论研究。该系统在界面处具有非常小的晶格失配，因此适合实现磁性隧道结的完全相干铁磁体/氧化物界面。在密度泛函理论的基础上，我们计算了界面各向异性常数K_{\rm i}$，表明该体系的界面垂直磁各向异性（PMA）为$K_{\rm i} \约1.2\,{\rm mJ/m^2}$，略小于Fe/MgO （$K_{\rm i} \约1.5—1.7$\,{\rm mJ/m^2}$）。对自旋轨道相互作用的二阶微扰分析表明，Fe/MgAl$_2$O$_4$和Fe/MgO $K_{\rm i}$的差异源于界面处自旋翻转散射项贡献的差异。我们提出在Fe/MgAl$_2$O$_4$界面中插入钨层是获得具有$K_{\rm i} \gtrsim 3\,{\rm mJ/m^2}$的巨大界面PMA的一种有前途的方法。
We present a theoretical study on interfacial magnetocrystalline anisotropy for Fe/MgAl$_2$O$_4$. This system has a very small lattice mismatch at the interface and therefore is suitable for realizing a fully coherent ferromagnet/oxide interface for magnetic tunnel junctions. On the basis of density functional theory, we calculate the interfacial anisotropy constant $K_{\rm i}$ and show that this system has interfacial perpendicular magnetic anisotropy (PMA) with $K_{\rm i} \approx 1.2\,{\rm mJ/m^2}$, which is a little bit smaller than that of Fe/MgO ($K_{\rm i} \approx$ 1.5--1.7$\,{\rm mJ/m^2}$). Second-order perturbation analysis with respect to the spin-orbit interaction clarifies that the difference in $K_{\rm i}$ between Fe/MgAl$_2$O$_4$ and Fe/MgO originates from the difference in contributions from spin-flip scattering terms at the interface. We propose that the insertion of tungsten layers into the interface of Fe/MgAl$_2$O$_4$ is a promising way to obtain huge interfacial PMA with $K_{\rm i} \gtrsim 3\,{\rm mJ/m^2}$.