Structural and FMR lineshape analysis of Mn Zn-ferrite nanoparticles

The Mn_0.25Zn_0.75Fe₂O₄ (MZF) nanoparticles of 3 to 5 nm size were synthesized by chemical coprecipitation method. The X-ray diffraction (XRD) patterns were well fitted with single phase spinel ferrite structure using Rietveld analysis as Fd-3m space group. The ferromagnetic resonance (FMR) spectra of MZF nanoparticles becomes more asymmetric with increase in particle size from 3 to 5 nm. The change in FMR line shape is attributed to the increase in ferromagnetic interactions and anisotropy in the system with increase in nanoparticles size. The decrease in total absorption of the FMR line with decreasing temperature at low temperatures indicates weak antiferromagnetic coupling between the octahedral and tetrahedral sublattices of the spinel ferrite system