Enhanced Room-Temperature Ferromagnetism Observed in SiO2-Coated CuO Nanostructures
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In this paper, the magnetic properties of pure CuO and SiO2-coated CuO nanocrystals were reported. Strongly enhanced room-temperature ferromagnetism was observed in SiO2-coated CuO nanocrystals, whose saturation magnetization is two orders of magnitude enhanced compared to that of the uncoated CuO nanocrystals. The mechanism of this enhancement was investigated. It points out the main origin of ferromagnetism in these CuO nanocrystals is the uncompensated surface state, so that the coating of SiO2 can effectively protect the surface state to improve the ferromagnetism in these CuO nanocrystals.
KeywordsNanocrystals Copper oxide Surface state Ferromagnetism
Scanning transmission electron microscopy
High-resolution transmission electron microscopy
Zero field cooled
This work is supported by the Higher Educational Science and Technology Program of Shandong Province, China (Grant No. J16LJ02); Natural Science Foundation of Shandong Province, China (ZR2016GM26); and the Key Laboratory of Public Security Management Technology in Universities of Shandong (Shandong Management University).