Effects of Mn_3O_4 on Magnetic Property,Microstructure and Resistivity of LiZn Ferrites

Iron-deficient LiZn ferrites with compositions of Li0.35Zn0.30Fe2.29MnxO4-δ+0.005mol%Bi2O3 and Li0.35Zn0.30Fe2.29O4-δ+0.005mol%Bi2O3+x/3mol%Mn3O4(x=0.02-0.08) were prepared by a conventional ceramic process at 920℃ and 950℃.Mn3O4 was added to the raw materials and calcined powders,respectively.Sintered at 920℃,adding optimum Mn3O4 to the raw materials enhances saturation magnetization Ms and remanence Br and decreases coercivity Hc,while adding Mn3O4 to the calcined powders has little effect on Ms and Br.Both kinds of samples have high Hc resulting from incomplete solid-state reaction at 920℃,whereas Hc is much lower in the sample with Mn3O4 adding to the raw materials.Sintered at 950℃,Hc of both kinds of samples decreases remarkably,whereas Hc is higher in the sample with Mn3O4 adding to the raw materials.Resistivities ρ in both kinds of samples are enhanced by optimum Mn3O4 adding and reaches the maximum when x is 0.06.Furthermore,the resistivity is higher in the sample with Mn3O4 adding to the raw materials.