Synthesis of low core loss Finemet/Ni0.5Zn0.5Fe2O4 composites by co-precipitation method

Finemet/Ni0.5Zn0.5Fe2O4 core/shell structure composites have been prepared by a co-precipitation method followed by a high temperature sintering process. The formation mechanism of the core/shell structures and the effects of oxygen partial pressure during the sintering process on the phase structure, microstructure, and magnetic properties were discussed. Low and high oxygen partial pressures resulted in the formation of crystal defects and a reduction of the magnetic properties of the composites. The magnetic properties could be adjusted by controlling the oxygen partial pressure and the optimal magnetic properties of the composites were obtained by sintering under an oxygen partial pressure of 10%. The resulting composite exhibited a high permeability of 61, a high saturation magnetization of 135.5 emu/g and a low core loss of approximately 30.5 mW/cm(3) at 100 kHz and 100 mT.