Tunneling magnetoresistance in Fe3Si/MgO/Fe3Si(001) magnetic tunnel junctions
Tunneling magnetoresistance in Fe3Si/MgO/Fe3Si(001) magnetic tunnel junctions
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DOI：
10.1063/1.4874837
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发表时间：
2014-05
影响因子：
4
通讯作者：
L. Tao;S. Liang;D. P. Liu;H. Wei;J. Wang;Xiufeng Han
中科院分区：
文献类型：
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作者：
L. Tao;S. Liang;D. P. Liu;H. Wei;J. Wang;Xiufeng Han
本文对Fe3Si/MgO/Fe3Si（001）磁性隧道结（MTJ）的隧道磁电阻（TMR）和自旋极化输运进行了理论研究。研究发现，自旋极化电导和偏置相关的TMR比对Fe3Si电极的结构非常敏感。通过对带结构的对称性分析，我们发现立方Fe3Si在费米能级上不存在自旋极化Δ1对称带。而在面内应变驱动下的四边形Fe3Si则呈现出Δ1状态的半金属性质。在零偏压下，预测了立方和四方Fe3Si电极的MTJs的巨大TMR比。然而，前者的界面共振传输导致的巨TMR比随着偏压的增大而迅速减小。对于后者，由于通过多数自旋Δ1通道的相干传输，巨大的TMR比可以保持更大的偏置。
We present a theoretical study of the tunneling magnetoresistance (TMR) and spin-polarized transport in Fe3Si/MgO/Fe3Si(001) magnetic tunnel junction (MTJ). It is found that the spin-polarized conductance and bias-dependent TMR ratios are rather sensitive to the structure of Fe3Si electrode. From the symmetry analysis of the band structures, we found that there is no spin-polarized Δ1 symmetry bands crossing the Fermi level for the cubic Fe3Si. In contrast, the tetragonal Fe3Si driven by in-plane strain reveals half-metal nature in terms of Δ1 state. The giant TMR ratios are predicted for both MTJs with cubic and tetragonal Fe3Si electrodes under zero bias. However, the giant TMR ratio resulting from interface resonant transmission for the former decreases rapidly with the bias. For the latter, the giant TMR ratio can maintain up to larger bias due to coherent transmission through the majority-spin Δ1 channel.