Influence of Ta2O5 Additive on Microstructure and Magnetic Properties of NiCuZn Ferrites

NiCuZn ferrites doped with Ta2O5 additive were prepared by solid-state reaction method. The influence of Ta2O5 additive on the microstructure, static magnetic properties and high frequency losses (P-cv) of NiCuZn ferrites were investigated. The results reveal that Ta2O5 can refine the grain of NiCuZn ferrites, and consequently reduce the sintering density. At the same time, the saturation induction and initial permeability of samples reduce monotonously with the increase of Ta2O5 content. The coercive force and resonance frequency, however, increase gradually. Furthermore, the high frequency losses (P-cv) firstly decrease and then increase, and the dominant factor of P-cv transforms from residual loss (P-r) to hysteresis loss (P-h), so the P-cv has a valley value when Ta2O5 content is 0.12wt%. The lowest P-cv is 139 mW/cm(3) at the conditions of 100 degrees C, 3 MHz and 10 mT, where P-h and P-r are 93 mW/cm(3) and 46 mW/cm(3), respectively.