Influence of Ta2O5–Co2O3 co-doping on the magnetic property of NiMgCuZn ferrites

NiMgCuZn ferrites co-doped with Ta2O5 and Co2O3 additives have been prepared by a solid-state reaction method. The influence of Ta2O5–Co2O3 (TC) additives on the microstructure, static magnetic properties and core losses (Pcv) at high frequency of NiMgCuZn ferrites has been investigated by scanning electron microscope (SEM), LCR meter and B–H analyzer. The results revealed that the composite additives reduce the sintering density via inhibiting the grain growth. According to Zagg’s report, the average grain sizes are smaller than 2.4 μm for different TC contents, hence all the samples have single domain structures. In addition, the saturation induction and initial permeability of the samples reduce monotonously with the increase of TC contents. While the coercivity and cutoff frequency show an opposite trend. For the samples with different TC contents, the core losses at high frequency have been discussed.