Interfacial structure and half-metallic ferromagnetism in Co2MnSi-based magnetic tunnel junctions
Interfacial structure and half-metallic ferromagnetism in Co2MnSi-based magnetic tunnel junctions
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DOI：
10.1103/physrevb.74.224439
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发表时间：
2006-12-01
影响因子：
3.7
通讯作者：
Miyazaki, T.
中科院分区：
文献类型：
--
作者：
Telling, N. D.;Keatley, P. S.;Miyazaki, T.
利用X射线吸收（XAS）和X射线磁圆二色性（XMCD）技术研究了Co2 MnSi全Heusler合金磁性隧道结中的铁磁/势垒界面。的界面区域的结构和磁性能的研究作为合金中的网站无序的程度的函数，并为不同程度的势垒氧化。在XAS谱中观察到依赖于L2（1）有序度的光电子散射特征。此外，发现Co和Mn原子的每3d空穴的磁矩是L2（1）有序度和势垒氧化态的敏感函数。值得注意的是，在XMCD光谱中观察到多重态结构，这表明磁矩的局部化程度，并且可能是由于合金中的半金属铁磁性（HMF）。这种多重态结构的大小似乎随制备条件而变化，并可用于确定组成原子在生产HMF中的作用，并检查屏障制备后保留半金属状态的方法。阻挡层氧化引起的磁结构的变化可以通过插入薄的Mg界面层来逆转，以抑制Mn在Co2 MnSi层中的氧化。
X-ray absorption (XAS) and x-ray magnetic circular dichroism (XMCD) techniques are utilized to explore the ferromagnetic/barrier interface in Co2MnSi full Heusler alloy magnetic tunnel junctions. Structural and magnetic properties of the interface region are studied as a function of the degree of site disorder in the alloy and for different degrees of barrier oxidation. Photoelectron scattering features that depend upon the degree of L2(1) ordering are observed in the XAS spectra. Additionally, the moments per 3d hole for Co and Mn atoms are found to be a sensitive function of both the degree of L2(1) ordering and the barrier oxidation state. Significantly, a multiplet structure is observed in the XMCD spectra that indicates a degree of localization of the moments and may result from the half-metallic ferromagnetism (HMF) in the alloy. The magnitude of this multiplet structure appears to vary with preparation conditions and could be utilized to ascertain the role of the constituent atoms in producing the HMF, and to examine methods for preserving the half-metallic state after barrier preparation. The changes in the magnetic structure caused by barrier oxidation could be reversed by inserting a thin Mg interface layer in order to suppress the oxidation of Mn in the Co2MnSi layer.