Breakthrough in studies on the two-dimensional magnetic materials by using X-ray absorption spectroscopy
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MoS2 nanosheets possesses outstanding electronic features, such as high charge-carrier mobility, tunable charge-carrier types, and high on/off ratio, which make them a very promising material in spintronics applications. Unfortunately, nowadays the inherent nonmagnetic property of common MoS2 nanosheets has hampered their practical applications in spintronics devices. How to render them with robust ferromagnetic property then becomes a great challenge. Toward this goal, Prefessor Wensheng Yan and associate Professor Zhihu Sun in Professor Shiqiang Wei’s group, at National synchrotron radiation laboratory, University of science and technology of China, proposed a phase-incorporation strategy to induce room-temperature ferromagnetism in nonmagnetic 2H-MoS2 semiconductor (Figure a). Experimentally, a two-step hydrothermal synthetic strategy was employed that could induce the formation of sulfur vacancy in the 2H-MoS2 nanosheets. The presence of these sulfur vacancy facilitated the transformation of the nearby 2H-MoS2 local lattice into 1T-hase, resulting in the formation of 1T-phase incorporated 2H-MoS2 nanosheets. The as-obtained 1T-incorporated 2H-MoS2 nanosheets have a Curie temperature of 395 K, as indicated by the magnetization measurements (Figure b). Soft X-ray absorption spectroscopy measurements and density-functional-theory calculations suggest that the observed ferromagnetism is originated from a 1T-MoS2-induced bandgap state near the Fermi level of 2H-MoS2 (Figure c). This work is published on J. Am. Chem. Soc. 2015, 137, 2622. The reviewer complimented that “It is a very interesting result because that to seek the room temperature ferromagnetic materials is always an urgent task and huge challenge. It would certainly attract people’s attention…”, and “The manuscripts describes an interesting observation of room temperature ferromagnetic nanosheets by modifying the host material....”

Room-temperature ferromagntism of 2H-MoS2 nanosheets induced by “phase-doping” of 1T-MoS2

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