The precursors of basic carbonates and ferric hydrate for ferrite were prepared by solid-state reaction at room temperature and characterized by TG-DSC. The nanometer spinel ferrites with the average size of 62nm were obtained by microwave heating at 600W and 10min and thermolysis at 550℃ and were studied by Laser Granularity Analyzer, XRD and SEM. The electromagnetic loss property was studied by the relative dielectric constant and relative magnetic permeability of the ferrites. The results show that Co2+ substituted partially Zn2+ in ZnFe2O4 that can improve observably the electromagnetic loss property of materials in 100~1800MHz and that Fe3+ was substituted small by Sm3+ in Co0.5Zn0.5Fe2O4 that can increase properly the electromagnetic loss property of materials in 100~1800MHz.

Key words: nano-ferrite, rare earth-doped, solid-state synthesis, electromagnetic loss