Effects of magnetic domain morphology on the magnetic spectrum and high‐frequency core losses of MnZn ferrites

Abstract

MnZn ferrites that exhibit low core losses at high frequencies are suitable for the integration and miniaturization of power conversion devices. To obtain low core losses at high frequencies, it is important to understand the underlying mechanism. In this work, MnZn ferrites with various grain sizes were produced by changing the sintering temperature. The relationship between domain morphology, dynamic magnetization behavior, and core losses at high frequencies was carefully investigated. As the average grain size approached the critical size of single‐domain state, the contribution of domain wall displacement to complex permeability decreased, while domain wall resonant frequency improved significantly, resulting in the suppression of residual loss at 3 MHz. As the average grain size increased, the domain morphology changed from a single‐domain state to a multidomain state, which increased the initial permeability and decreased hysteresis loss. However, the number of domain walls increased, causing a significant decrease in the domain wall resonant frequency, and resulting in a sharp increase in residual loss. These results provide valuable insights into reducing high‐frequency core losses in MnZn ferrites by domain engineering.

Contribution of Magnetization Mechanisms in MnZn Ferrites with Different Grain Sizes and Sintering Densification

“…In summary, among the studies focusing on magnetic properties, composition, additives, sintering processes, and the spectra of complex permeability [27][28][29][30][31][32][33], few have delved into the contribution of magnetization mechanisms in MnZn ferrites as a function of grain size and its relationship with the sintering temperature. This research presents an exploration of the magnetization mechanisms in MnZn ferrites at different sintering temperatures, discussing the findings in conjunction with the fitting results of permeability spectrum dispersion.…”