Journal of Magnetism and Magnetic Materials

The purpose of this particular study is the development of a high frequency –1 to 3 MHz – stable MnZn ferrite. The notion under which the study was held was the preliminary investigation of the dissipation mechanisms, and subsequently the hypothesis of the predominance of one. Accordingly the path of enhancement commenced with a selection of high frequency MnZn ferrite as the base – namely one exhibiting high ferromagnetic resonance (FMR) already – and the selective addition of Co2+ and Mg2+. Arguably the offspring of the study was a superb high frequency ferrite, stable throughout the temperature spectrum, 25–115 °C, presenting power losses as low as 87 mW cm−3 (1 MHz, 50 mT, 85 °C) and 319 mW cm−3 (3 MHz, 30 mT, 85 °C). Initial permeability (10 kHz, 0.1 mT) remains higher than the value of 850 (25–115 °C) and FMR appears no earlier than 7.1 MHz. To the authors’ knowledge these values are among the best reported.