We demonstrate herein a basic approach to a new type of exchange-coupled iron oxide-based core/shell nanocubes consisting of an antiferromagnetic (AFM) core of ferrous oxide (wustite, FeO) surrounded by a ferrimagnetic (FM) shell of ferrite (spinel, γ-Fe2O3 or Fe3O 4). By coupling with AFM core, effective blocking temperature of FM moments is strongly enhanced up to Néel temperature (TN 198 K) of AFM core. This is assigned to contribution of an extra anisotropy induced by exchange bias at the interface between AFM and FM components in the nanocubes. Because of this special coupling structure, the high stability of FM moments can be achieved even at very small volume fraction of AFM with respect to FM matrix, thus significantly eliminate contribution of AFM to the magnetization of whole coupling system, suggesting a new hybrid structure for magnetic devices applications.
ASJC Scopus subject areas
- Physics and Astronomy(all)