High temperature magnetic order in zinc sulfide doped with copper

We report the first observation of magnetic order above room temperature in zinc sulfide doped with Cu2+ made by a simple sintering process and detected by ferromagnetic resonance (FMR), SQUID magnetometry and the mu SR experiments. FMR study shows nonzero absorption above room temperature indicating a high value of Curie temperature. Field-cooled and zero-field-cooled magnetization data indicate a bifurcation at about 300 K. This temperature is considered to be the blocking temperature at ferromagnetic nanosized regions, which appear to exist in the sample of ZnS doped with copper. The muon spin rotation measurements confirm highly nonuniform magnetic order. It was shown that about 25% of the sample volume fraction exhibits strong magnetism. (C) 2011 Elsevier Ltd. All rights reserved.