Two-dimensional (2D) layered materials and their heterostructures have opened a new avenue for next-generation spintronic applications, benefited by their unique electronic properties and high crystallinity with an atomically flat surface. Here, we report magnetoresistance of vertical magnetic spin-valve devices with multi-layer (ML) MoSe2 and its heterostructures with few-layer graphene (FLG). We employed a micro-fabrication procedure to form ultraclean ferromagnetic–non-magnetic–ferromagnetic interfaces to elucidate the intrinsic spin-transferring mechanism through both an individual material and combinations of 2D layered materials. However, it is revealed that the polarity of tunneling magnetoresistance (TMR) is independent of non-magnetic spacers whether the spin valve is composed of a single material or a hybrid structure, but it strongly depends on the interfaces between ferromagnetics (FMs) and 2D materials. We observed positive spin polarizations in ML-MoSe2 and FLG/ML-MoSe2/FLG tunnel junctions, whereas spin-valve devices comprised of FLG/ML-MoSe2 showed a reversed spin polarization and demonstrated a negative TMR. Importantly, in Co/FLG/ML-MoSe2/FLG/NiFe devices, the polarization of spin carriers in the FM/FLG interface remained conserved during tunneling through MoSe2 flakes in spin-transferring events, which is understandable by Julliere’s model. In addition, large TMR values are investigated at low temperatures, whereas at high temperatures, the TMR ratios are deteriorated. Furthermore, the large values of driving ac-current also quenched the amplitude of TMR signals. Therefore, our observations suggest that the microscopic spin-transferring mechanism between ferromagnetic metals and 2D materials played a momentous role in spin-transferring phenomena in vertical magnetic spin-valve junctions.

中文翻译：

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垂直 FLG/MoSe2/FLG 的多异质结构自旋阀结

二维 (2D) 层状材料及其异质结构为下一代自旋电子应用开辟了一条新途径，受益于其独特的电子特性和原子级平坦表面的高结晶度。在这里，我们报告了具有多层 (ML) MoSe2 的垂直磁性自旋阀器件及其具有少层石墨烯 (FLG) 的异质结构的磁阻。我们采用微制造程序来形成超洁净的铁磁-非磁-铁磁界面，以通过单个材料和二维层状材料的组合阐明固有的自旋转移机制。然而，揭示了隧道磁阻（TMR）的极性与非磁性间隔物无关，无论自旋阀是由单一材料还是混合结构组成，但它在很大程度上取决于铁磁材料 (FM) 和 2D 材料之间的界面。我们在 ML-MoSe2 和 FLG/ML-MoSe2/FLG 隧道结中观察到正自旋极化，而由 FLG/ML-MoSe2 组成的自旋阀装置显示出反向自旋极化并表现出负 TMR。重要的是，在 Co/FLG/ML-MoSe2/FLG/NiFe 器件中，FM/FLG 界面中自旋载流子的极化在自旋转移事件中穿过 MoSe2 薄片期间保持保守，这可以通过 Julliere 模型理解。此外，在低温下研究了大的 TMR 值，而在高温下，TMR 比率会恶化。此外，驱动交流电流的大值也抑制了 TMR 信号的幅度。所以，