Analysis of losses in NiO doped MnZn ferrites

Manganese–zinc (MnZn) ferrites doped with NiO addition were prepared by solid-state reaction method. Losses (PL) were divided into hysteresis loss (Ph), eddy current loss (Pe) and residual loss (Pr), temperature and frequency characteristics of each loss, and the ratio of each loss to the total losses have been discussed. Ph increased monotonously with increasing NiO, and its variation can be explained by the relation: Ph∝1/μi3. Pe first reduced before achieving its minimum, and then rose gradually. The variation of Pe was not consistent with the classical expression, Pe,cl ∝ D2/ρ, with D as grain size, and the excess loss (Pe,exc) can contribute to the Pe. Pr decreased gradually with increasing NiO due to D's decrease and fr's increase, with fr as resonance frequency. Finally, the sample doped with 0.10 wt.% NiO showed the lowest losses of 175 kW/m3 at 100 °C, 0.5 MHz and 50 mT, and of 207 kW/m3 at 100 °C, 1 MHz and 30 mT.