Spin Polarization-Assisted Dopant Segregation at a Coherent Phase Boundary
Spin Polarization-Assisted Dopant Segregation at a Coherent Phase Boundary
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相干相边界处的自旋极化辅助掺杂剂偏析
DOI：
10.1021/acsnano.1c07449
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发表时间：
2021-12-08
期刊：
影响因子：
17.1
通讯作者：
Ikuhara, Yuichi
中科院分区：
文献类型：
--
作者：
Jiang, Yixiao;Li, Hongping;Ikuhara, Yuichi
共格相边界由于其低的界面能和缺乏杂质的捕获位点而被广泛预期为无偏析边界。在这里，我们报告了一个平衡偏析的W原子在完全相干梯田的Fe 3 O 4（111）/Fe 2 O3（0001）相界，这是以前从未预料到的。通过对原始和掺W的Fe 3 O 4/Fe 2 O3相界的比较，发现界面处O原子的自旋极化对W原子的周期性偏聚起着重要作用。具有大磁矩的非寻常自旋极化O原子周期性地排列在原始相边界的界面O平面上。在该边界处掺杂W之后，W原子将选择性地取代Fe 2 O3中与三个自旋极化的O原子直接键合的Fe原子，从而导致自旋极化的O原子的磁矩的完全中和。这些发现表明，相干相边界能够捕获杂质，并且局部自旋极化是掺杂剂偏析的驱动力之一，这表明元素掺杂是定制磁性材料和器件中边界物理性质的有效方法。
Coherent phase boundaries are widely expected as segregation-free boundaries due to their low interfacial energies and lack of trapping sites for impurities. Here, we report an equilibrium segregation of W atoms at fully coherent terraces of a Fe3O4(111)/Fe2O3 (0001) phase boundary that was never expected previously. Through comparison of pristine and W-doped Fe3O4/Fe2O3 phase boundaries, it is revealed that the spin polarization of O atoms at the interface plays an important role in the periodic segregation of W atoms. Unusual spin-polarized O atoms with large magnetic moments are periodically arranged in the interfacial O plane of the pristine phase boundary. After doping of W at this boundary, W atoms will selectively substitute the Fe atoms of Fe2O3 that directly bond with three spin-polarized O atoms, thereby resulting in the complete neutralization of the magnetic moments of the spin-polarized O atoms. These findings reveal that coherent phase boundaries are able to trap impurities and local spin polarization is one of the driving forces for dopant segregation, suggesting that elemental doping is an efficient way for tailoring the physical properties of boundaries in magnetic materials and devices.