Effect of Sintering Temperature on the Microstructural, Magnetic and Microwave Properties of Magnesium-Manganese Ferrites

High quality spinelmagnesium-manganese (Mg-Mn) microwave ferrites were fabricated by conventional mixed oxide process. In this study, we report the influence of sintering temperature on the microstructures, and on the magnetic and microwave properties of Mg-Mn ferrites. Green compacts of Mg-Mn ferrites were sintered at 1250 to 1350 degrees C for 4 h. XRD patterns revealed that all sintered Mg-Mn ferrites had a cubic spinel structure. According to fracture surface SEM images, the 1350 degrees C sintered samples exhibited the best densification microstructure. Experimental results also showed that the 1300 and 1350 degrees C sintered samples exhibited a close saturation magnetization and the real part of alternative-current magnetic susceptibility from 50 to 2500 Hz. Among all as-prepared Mg-Mn ferrites, the 1350 degrees C sintered samples had the lowest magnetic energy loss at the resonance frequency of 15 kHz, the narrowest magnetic resonance linewidth of 330 G at a frequency of about 9.86 GHz, and the highest Qxf value of 940 GHz at a frequency of about 6.5 GHz.