High-frequency magnetic properties of Co-Ti substituted barium ferrites prepared by modified chemical coprecipitation method

Co-Ti substituted barium ferrites were prepared by a modified chemical coprecipitation method. Microstructures and high-frequency magnetic properties were investigated by X-ray diffraction (XRD) transmission electron microscopy (TEM) scanning electron microscopy (SEM) and measurements of complex permeability spectra. Barium ferrites with Co-Ti substitution x=1.0 have the highest permeability and the lowest magnetic resonant frequency f_ros and f_ros can be changed continuously with changing Co-Ti substitution in the hyper-frequency region while keeps its high value at the same time. A higher sintering temperature corresponds to higher and lower f_ros due to the grain growth. The d.c. electrical resistivity for all samples was above 10⁸ cm.