Effect of CaCu3Ti4O12 dopant on the magnetic and dielectric properties of high-frequency MnZn power ferrites

Abstract To obtain miniaturized, lightweight, and integrated power conversion devices, the core material must be suitable for operation at higher frequencies (in the megahertz range) and must exhibit excellent performance, specifically, low core losses. In this study, MnZn power ferrites, a common core material, were doped with calcium copper titanate (CCTO) using a solid-state reaction method. The effects of CCTO doping (0.0–0.5 wt%) on the structural, magnetic, and dielectric properties of the MnZn ferrites were studied. The addition of 0.2 wt% CCTO to the MnZn ferrites improved the grain uniformity and decreased the porosity; thus, the material exhibited a fine microstructure. In addition, the saturation induction, initial permeability, and resistivity of the MnZn ferrites were increased, and the high-frequency core losses were suppressed. The core losses of the 0.2 wt% CCTO sample were only 495 kW/m3 at 3 MHz, 30 mT, and 25 °C. The lower core losses resulted mainly from reductions in the hysteresis loss and eddy current loss. The real permittivity of two representative MnZn ferrite samples was also investigated. The application of state-of-the-art MnZn ferrites with superior electromagnetic properties in high-frequency power conversion devices is anticipated. This study demonstrates that adding a dielectric material improves the electromagnetic properties of MnZn power ferrites.