二維材料結構中高度純淨界面的自旋傳輸現象

Abstract

二維材料與磁性自旋閥的整合被期望能夠開啟自旋電子學裝置的潛力。然而，目前的實際情況仍然偏離預期。大多數研究將這樣的差距歸因於在二維材料與其鐵磁性電極界面之間的汙染。我們研發了能製作超高潔淨界面的製程方法。通過在真空環境中一次性且同步地沉積非對稱鐵磁電極在懸浮的二維材料上，可以有效地避免氧化和界面汙染的負面效應。在我們的研究中，基於石墨烯的自旋閥在界面與鐵磁材料呈現強烈的相互作用，產生比起以往的實驗結果更高的磁阻值。不僅如此，鐵磁性電極可以展現固有的矯頑力，而不受污染物干擾，這使我們能夠藉由額外的反鐵磁材料來製造具有可控矯頑力的自旋閥。此外，基於二硫化鉬的自旋閥的金屬鄰近效應和主導的自旋過濾效應，呈現出顯著的負磁阻值。這些發現不僅增強了自旋電子學在實際應用中的可行性，還探索了可延伸更多功能性的自旋閥機制。我們的方法提供了一條有效探討鐵磁性電極與二維材料之間固有相互作用的反應途徑。

The integration of 2D materials and magnetic spin valves is expected to unlock the potential of spintronics devices. However, the current practical situation still deviates from expectations. Most studies attribute such inconsistencies to the challenge of achieving a contamination-free interface between the 2D material barrier and its ferromagnetic contacts. Here, we demonstrate a novel approach to ensure an ultrahigh clean interface. By synchronously depositing asymmetric contacts on a suspended 2D material in a single step within a vacuum environment, the detrimental effects of oxidation and breaks in the interface can be effectively avoided. In our study, graphene-based spin valves present a strong interaction at the interface that gives rise to exceptional magnetoresistance values. Ferromagnetic electrodes can exhibit inherent coercivity without pollutant disturbance, allowing us to manufacture a spin valve with controllable coercivity by incorporating additional antiferromagnetic materials. Moreover, MoS2-based spin valves exhibit remarkable negative magnetoresistance values due to the metallic proximity effect and the predominant spin filter effect. These findings not only enhance the feasibility of practical applications in spintronics but also explore the mechanisms of spin valves with rich functionality. Our method evidently provides a path to investigate the intrinsic response from the interplay between ferromagnetic electrodes and 2D materials.