Ferromagnetism in Fe-doped MgO nanoparticles

摘要

This work reports the study on magnetic properties of Mg_(1-x)Fe_xO (x = 0, 0.05 and 0.07) nanoparticles prepared by the polymer pyrolysis method. Phase, valence states and magnetic properties of these samples were characterized using X-ray diffraction (XRD), transmission electron microscopy, X-ray absorption near edge structure (XANES) and vibrating sample magnetometer (VSM), respectively. The XRD results show that the samples have a phase nature of the cubic structure with constant crystallite size of 25 ± 2 nm. XANES spectra reveal the existence of Fe~(3+) ions in the samples. VSM measurements exhibit the room temperature ferromagnetism with a maximum magnetization of 1.60 emu/g for x = 0.07. The origin of ferromagnetism is fitted on the bound magnetic polaron (BMP) model to indicate the numbers of BMPs involving overlapping of polarons via oxygen vacancy defects.