Effects of Bi2O3 addition on power loss characteristics of low-temperature-fired NiCuZn ferrites

NiCuZn ferrites doped with different Bi2O3 contents (0-1 wt%) were prepared through conventional ceramic technology. Phase composition, microstructure and magnetic properties, especially power loss characteristic of these samples were investigated. In doping range, Bi2O3 did not introduce heterozygous phases. Initial permeability and saturation flux density (Bs) initially increased and then decreased as Bi2O3 content increased. Maximum initial permeability and Bs were obtained with 0.25 wt% and 0.5 wt% Bi2O3, respectively. The variation in Bs with doping content was consistent with the variation in density. The variation in coercive force (Hc) was opposite to the variation in Bs. The sample doped with 0.25 wt% Bi2O3 obtained the lowest power loss, regardless of different frequencies and induction conditions. Therefore, NiCuZn ferrite with 0.25 wt% Bi2O3 was the best choice for applications in chip power magnetic devices or modules.