Structural, chemical, and electronic properties of the Co2MnSi(001)/MgO interface
Structural, chemical, and electronic properties of the Co2MnSi(001)/MgO interface
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DOI：
10.1103/physrevb.87.184418
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发表时间：
2013-05-17
影响因子：
3.7
通讯作者：
Cinchetti, Mirko
中科院分区：
文献类型：
--
作者：
Fetzer, Roman;Wuestenberg, Jan-Peter;Cinchetti, Mirko
由铁磁 (FM) 电极和 MgO 作为绝缘层构成的先进磁隧道结的性能在很大程度上取决于 FM/绝缘体界面的特性。在这里，我们通过俄歇电子能谱、低能电子衍射和低能光电发射研究了钴基霍斯勒化合物 Co2MnSi (CMS) 和 MgO 之间的界面形成。研究针对不同的退火温度 (T-A) 和 MgO 层覆盖范围（4、6、10、20 和 50 ML）进行。薄 MgO 顶层 (t(MgO) 10 ML，MgO 层表面表现出明显改善的晶体结构，因此只有少量的吸附物。我们将这些发现归因于界面处发生的 MgO 错配位错，在整个 MgO 层中诱导进一步的缺陷，持续时间至少为 10 ML。此外，获得了 CMS/MgO 界面的自旋偏振光发射光谱，MgO 覆盖范围高达 20 ML，显示出清晰的在所有情况下，正自旋极化都接近费米能 (E-F)。
The performance of advanced magnetic tunnel junctions built of ferromagnetic (FM) electrodes and MgO as an insulating barrier depends decisively on the properties of the FM/insulator interface. Here we investigate interface formation between the Co-based Heusler compound Co2MnSi (CMS) and MgO by means of Auger electron spectroscopy, low-energy electron diffraction, and low-energy photoemission. The studies are performed for different annealing temperatures (T-A) and MgO layer coverages (4, 6, 10, 20, and 50 ML). Thin MgO top layers (t(MgO) 10 ML, the MgO layer surface exhibits clearly improved crystalline structure and hence only marginal amounts of adsorbates. We attribute these findings to MgO misfit dislocations occurring at the interface, inducing further defects throughout the MgO layer for up to at least 10 ML. Furthermore, spin-polarized photoemission spectra of the CMS/MgO interface are obtained for MgO coverages up to 20 ML, showing a clear positive spin polarization near the Fermi energy (E-F) in all cases.