Microstructures and magnetic properties of Bi-substituted NiCuZn ferrite

Abstract

The effects of Bi3+ substitution on the microstructures and properties of low-temperature fired NiCuZn ferrites have been investigated. It is found that Bi3+ ions can enter into the ferrite lattice and consequently enhance the grain growth and densification in the sintering process due to the activation of the lattice, which in turn lead to an increase of quality factor and static permeability. Bi3+ substitution for Fe3+ is beneficial to forming the spinal phase and lowers the sintering temperature to about 900 °C. Pcv (power loss) was analyzed by dividing Pcv into Ph (hysteresis loss) and Pe+Pr (eddy current loss and residual loss) from the frequency dependence of the power loss. Due to the compact and uniform microstructures, and high sintering density, relatively low losses were obtained in the Bi-substituted samples.