Interface-resolved study of magnetism in MgO/FeCoB/MgO trilayers using x-ray standing wave techniques
Interface-resolved study of magnetism in MgO/FeCoB/MgO trilayers using x-ray standing wave techniques
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使用 X 射线驻波技术对 MgO/FeCoB/MgO 三层膜中的磁性进行界面解析研究
DOI：
10.1103/physrevb.107.075416
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发表时间：
2023
影响因子：
3.7
通讯作者：
D. Kumar
中科院分区：
文献类型：
--
作者：
Md. Shahid Jamal;Pooja Gupta;I. Sergeev;O. Leupold;D. Kumar
用掠入射核共振散射(GINRS)和X射线驻波(XSW)技术研究了MgO-FeCoB-MgO三层膜界面。本方法的高深度选择性使人们能够独立地测量FeCoB的两个界面上的磁性和结构，即FeCoB-on-FeO和FeCoB-on-FeCoB，产生了有趣的结果，即两个界面都不对称。在FeCoB-on-MgO界面处的高密度层具有增强的超精细磁场，表明两种界面的生长机制不同。方位角相关的磁光克尔效应测量表明，三层膜中存在异常的单轴磁各向异性(UMA)。一项与温度相关的现场研究发现，这种UMA随着温度的升高而系统地减少。在450℃时，三层膜变得各向同性，矫顽力增加了一个数量级。界面的不对称性又可以通过硼从FeCoB界面层向附近的MgO层的扩散来解释。在缺硼的FeCoB层中观察到应力诱导的UMA，并与块体FeCoB层叠加，并被发现是导致异常UMA的原因。UMA和矫直力随温度的变化可以通过内应力的变化以及FeCoB块体和界面层之间的耦合来理解。
Interfaces in the MgO-FeCoB-MgO trilayer have been studied with grazing incident nuclear resonance scattering (GINRS) using the x-ray standing waves (XSW) technique. High depth selectivity of the present method allows one to measure magnetism and structure at the two interfaces of FeCoB, namely, FeCoB-on-MgO and MgO-on-FeCoB, independently, yielding an intriguing result that both interfaces are not symmetric. A high-density layer with an increased magnetic hyperfine field at the FeCoB-on-MgO interface suggests different growth mechanisms at the two interfaces. The azimuthal angle-dependent magneto-optic Kerr effect measurements reveal the presence of unusual uniaxial magnetic anisotropy (UMA) in the trilayer. An in-situ temperature-dependent study discovered that this UMA systematically reduces with temperature. The trilayer becomes isotropic at 450C with an order-of-magnitude increase in coercivity. The asymmetry at the interfaces is, in turn, explained by boron diffusion from the FeCoB interface layer into the nearby MgO layer. Stress-induced UMA is observed in the boron-deficient FeCoB layer, superimposed with the bulk FeCoB layer, and found to be responsible for unusual UMA. The temperature-dependent variation in the UMA and coercivity can be understood in terms of variations in the internal stresses and coupling between FeCoB bulk and the interface layer.
影响因子：
3.7
作者：
Hindmarch, A. T.;Rushforth, A. W.;Gallagher, B. L.
通讯作者：
Gallagher, B. L.
影响因子：
8.6
作者：
A. Hindmarch;C. Kinane;M. Mackenzie;J. Chapman;M. Henini;D. Taylor;D. Arena;J. Dvorak;B. Hickey-B
通讯作者：
A. Hindmarch;C. Kinane;M. Mackenzie;J. Chapman;M. Henini;D. Taylor;D. Arena;J. Dvorak;B. Hickey-B