Effect of annealing on cation distribution and magnetic properties of nano sized Mn0.34Co0.66Fe2O4 microwave ferrites

Microwave spinel ferrites are ubiquitous in systems that receive, send, and manipulate electromagnetic signals across very high frequency to quasi-optical frequency bands. This paper elaborates the effects of annealing on structural and magnetic properties of the Mn0.34Co0.66Fe2O4 ferrite nano-particles, synthesised by solvothermal method. The Rietveld refinement of XRD data reveals that nanoparticles are crystallized in spinel structure with Fd-3m space group and on annealing the Mn2+ ions migrates from tetrahedral to octahedral site. The FESEM microstructures reveal that grain size increase from 30 nm to 200 nm on annealing and morphology of the particles changes from spherical to rhombohedral. The magnetic data analysis shows that on annealing the magnetization improves significantly from Ms = 59.23 emu/g to Ms = 86.80 emu/g. Magnetocrystalline anisotropy and coercivity increased significantly on annealing. The change in magnetic properties on annealing is strongly correlated to redistribution of Mn2+ cations on different sites.