Insights into the room temperature magnetism of ZnO/Co_(3)O_(4) mixtures

摘要

The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based diluted magnetic semiconductors is still an unclear topic. The present work concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co_(3)O_(4) mixtures without thermal treatment. In this study, it is shown that the magnetism seems to be related to surface reduction of the Co_(3)O_(4) nanoparticles, in which, an antiferromagnetic Co_(3)O_(4) nanoparticle (core) is surrounded by a CoO-like shell. This singular superficial magnetism has also been found in other mixtures with semiconductors such as TiO_(2) and insulators such as Al_(2)O_(3).