Probing the Buried Magnetic Interfaces
2016
Liu, Wenqing | Zhou, Qionghua | Chen, Qian | Niu, Daxin | Zhou, Yan | Xu, Y. B. (Yongbing) | Zhang, Rong | Wang, Jinlan | van der Laan, Gerrit
Understanding magnetism in ferromagnetic metal/semiconductor (FM/SC) heterostructures is important to the development of the new-generation spin field-effect transistor. Here, we report an element-specific X-ray magnetic circular dichroism study of the interfacial magnetic moments for two FM/SC model systems, namely, Co/GaAs and Ni/GaAs, which was enabled using a specially designed FM₁/FM₂/SC superstructure. We observed a robust room temperature magnetization of the interfacial Co, while that of the interfacial Ni was strongly diminished down to 5 K because of hybridization of the Ni d(eg) and GaAs sp³ states. The validity of the selected method was confirmed by first-principles calculations, showing only small deviations (<0.02 and <0.07 μB/atom for Co/GaAs and Ni/GaAs, respectively) compared to the real FM/SC interfaces. Our work proved that the electronic structure and magnetic ground state of the interfacial FM₂ is not altered when the topmost FM₂ is replaced by FM₁ and that this model is applicable generally for probing the buried magnetic interfaces in the advanced spintronic materials..
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