Effects of calcination temperature on the microstructure and magnetic properties of low-temperature-fired Ni_0.4Cu_0.15Zn_0.45Fe_1.98O_3.97 ferrites

This study investigates the critical role of calcination temperature in determining the microstructural and magnetic properties of NiCuZn ferrites, with a specific emphasis on improving their DC-bias superposition characteristics. Our findings show that higher calcination temperatures cause an increase in sintered density and grain size, as well as the formation of a Cu-rich segregated phase at grain boundaries. Notably, ferrites calcined at 950 °C exhibited superior DC-bias superposition properties, which were attributed to the presence of a nonmagnetic copper-rich phase that modulates magnetic properties. NiCuZn ferrites with enhanced DC-bias superposition characteristics exhibit a more stable incremental permeability under a DC-bias magnetic field, which is essential for maintaining inductance at high currents. These findings highlight the critical role of calcination temperature in optimizing the magnetic performance of NiCuZn ferrites, providing useful insights for the development of advanced materials for high-frequency power.