A facile way to regulating room-temperature ferromagnetic interaction in Co-doped ZnO diluted magnetic semiconductor by reduced graphene oxide coating

Realizing room-temperature ferromagnetic interactions in diluted magnetic semiconductors is a precondition to future application of next-generation spin-based information technologies. However, searching capable methods to tailor the inherent magnetic coupling is still a great challenge. Here, a strategy for effective manipulating the ferromagnetism of 1% Co doped ZnO (Co-ZnO) is developed. Graphene oxide (GO) was coated on the surface of Co-ZnO, and was in-situ reduced by hydroxylamine, which brought about larger oxygen vacancy density and significant changes in saturation magnetization, due to the hybridization of pi orbits of reduced GO and 3d orbits of Co2+. The structure and origin of the ferromagnetism have been investigated by XRD, SEM, HREM, UV-Vis, FTIR, XPS, and PPMS. And the saturation magnetization of Co-ZnO increased from 0.002 to 0.013 emu.g(-1) after coated by reduced GO. This strategy may provide a new way for regulating the density and nature of defects in ZnO, and open up a possibility to manipulate the ferromagnetism of diluted magnetic semiconductors. (C) 2018 Published by Elsevier B.V.