Monodisperse Fe1-xO nanoparticles (NPs) with a mean size of 21.7 ± 2.1 nm were prepared by the thermal decomposition of iron(III) oleate complex at 380 °C using oleic acid as the solvent. Variation in their composition was monitored using XRD for a period of 120 days under ambient conditions, under which the dominant phase changed from wüstite to a spinel-type iron oxide phase. HR-TEM images and absorption spectra of the 10-day sample further revealed an FeO/spinel-type phase core-shell structure. Exchange-bias coupling on the interfaces between the wüstite and the spinel-type phase accompanied the variation in composition. The dependence of HE on temperature demonstrates that the HE onset temperature is approximately 200 K, which correlates with the TN of bulk FeO.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films