Synthesis of ultrafine SrLaxFe12−xO19 particles with high coercivity and magnetization by sol-gel method

M-type hexaferrite SrLaxFe12−xO19 (x = 0 − 0.2) powders were synthesized by sol-gel method. The precursor gels were calcined at temperatures from 650 °C to 1050 °C in air for 2 h to obtain the SrFe12O19 phase. The thermal decomposition of gels was investigated by DTA/TGA. Samples of substituted ferrites were characterized by various experimental techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). A very high magnetic coercivity (iHC) of 7.0 kOe with the magnetization at 13.5 kOe of 66 emu/g at room temperature was observed for the sample of La concentration x = 0.05 calcined at 850 °C.