Origin of the Large Dispersion of Magnetic Properties in Nanostructured Oxides: FexO/Fe3O4 Nanoparticles as a Case Study

Authors:
M. Estrader, A. López-Ortega, I.V. Golosovsky, S. Estradé, A.G. Roca, G. Salazar-Alvarez, L. López-Conesa, D. Tobia, E. Winkler, J.D. Ardisson, W.A.A. Macedo, A. Morphis, M. Vasilakaki, K.N. Trohidou, A. Gukasov, I. Mirebeau, O.L. Makarova, R.D. Zysler, F. Peiró, M.D. Baró, L. Bergström, and Josep Nogués
The year of the publication:
2015
Journal:
NanoScale, Journal of Royal Society of Chemistry vol. 7 3002
Abstract:

The intimate relationship between stoichiometry and physicochemical properties in transition-metal oxides makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct relationship between structure-morphology and functionalities is often complicated. In this regard, in the FexO/Fe3O4 system a largely unexplained broad dispersion of magnetic properties has been observed. Here we show, thanks to a comprehensive multi-technique approach, a clear correlation between the magneto-structural properties in large (45 nm) and small (9 nm) FexO/Fe3O4 core/shell nanoparticles that can explain the spread of magnetic behaviors. The results reveal that while the FexO core in the large nanoparticles is antiferromagnetic and has bulk-like stoichiometry and unit-cell parameters, the FexO core in the small particles is highly non-stoichiometric and strained, displaying no significant antiferromagnetism. These results highlight the importance of ample characterization to fully understand the properties of nanostructured metal oxides.

Scroll To Top