Nitrogen Tuned Charge Redistribution and Orbital Reconfiguration in Fe/MgO Interface for Significant Interfacial Magnetism Tunability
Nitrogen Tuned Charge Redistribution and Orbital Reconfiguration in Fe/MgO Interface for Significant Interfacial Magnetism Tunability
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DOI：
10.1002/adfm.201806677
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发表时间：
2018-12
影响因子：
19
通讯作者：
Shiru Wang;Mingke Yao;Zirun Li;C. Feng;Lei Wang;Xiaolei Tang;Peng Kang;Bin Zhang;W. Mi-W.
中科院分区：
文献类型：
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作者：
Shiru Wang;Mingke Yao;Zirun Li;C. Feng;Lei Wang;Xiaolei Tang;Peng Kang;Bin Zhang;W. Mi-W.
调制铁磁金属（FM）/金属氧化物（MO）界面的轨道配置对于获得可控的界面磁性以构建节能磁存储器和逻辑器件至关重要。传统的轨道调控工作依赖于外场，如电场、温度场、应力场等。本文提出了一种新的轨道调制策略，通过改变FM/MO界面的配位环境，引入氮（N）。通过在N2气氛下制备Fe/MgO双层膜，N原子占据Fe晶格的间隙位置，这引起Fe/MgO界面处的电荷重新分布，并且随着面外轨道占有率的增加而切换Fe的显著轨道重构。因此，轨道磁性被有效地调谐，这显著地增强了界面磁各向异性能0.6 erg cm−2，并实现了从面内到垂直方向的宽磁各向异性可调谐性。此外，用于保持垂直磁各向异性的Fe厚度从小于1 nm扩展到3 nm，这有利于提高纳米级器件的信噪比和稳定性。这些发现提供了一种与外场无关的轨道工程策略，用于在FM/MO异质界面处定制轨道控制性能，这实际上促进了磁存储和逻辑器件的发展。
Modulating the orbital configuration of ferromagnetic metal (FM)/metal‐oxide (MO) interfaces is crucial for obtaining a controllable interfacial magnetism for constructing energy‐efficient magnetic memory and logic devices. The traditional works of orbital regulation depend on external fields, such as electric field, temperature field, and stress field. This work proposes a novel orbital modulation strategy by modifying the coordination environment of FM/MO interface with nitrogen (N) incorporation. By preparing a Fe/MgO bilayer at a N2 atmosphere, N atoms occupy the interstitial sites of the Fe lattice, which induces a charge redistribution at the Fe/MgO interface and toggles a prominent orbital reconstruction of Fe with an increment of out‐of‐plane orbital occupancy. Therefore, the orbital magnetism is tuned effectively, which remarkably strengthens the interfacial magnetic anisotropy energy by 0.6 erg cm−2 and enables a broad magnetic anisotropy tunability from in‐plane to perpendicular direction. Besides, the Fe thickness for maintaining perpendicular magnetic anisotropy extends from less than 1 to 3 nm, which is favorable for improving the signal‐to‐noise ratio and stability of devices in nanoscale. These findings provide an external‐field‐independent strategy of orbital engineering for tailoring obit‐controlled performance at FM/MO heterointerfaces, which practically advances the magnetic storage and logic devices.