Study of strontium ferrites substituted by lanthanum on the structural and magnetic properties

Abstract M-type strontium ferrites, Sr 0.8 La 0.2 Fe 12 O 19 have been synthesized by conventional ceramic process. The effects of lanthanum addition and sintering temperature on microstructures and magnetic properties of SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 samples were investigated. Microstructural analysis of the SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 specimens, sintered at different temperatures revealed that average grain sizes of SrFe 12 O 19 ferrites were larger than that of Sr 0.8 La 0.2 Fe 12 O 19 ferrite and increased with increasing sintering temperature. The X-ray diffraction (XRD) results confirmed the strontium hexagonal ferrite phase of SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 compounds. A maximum coercivity value of 4850 Oe and maximum saturation magnetization value of 102 emu/g were obtained for the SrFe 12 O 19 ferrite sintered at 1150 °C and for the SrFe 12 O 19 and Sr 0.8 La 0.2 Fe 12 O 19 ferrites sintered at 1300 °C, respectively. The remanence (Mr) of Sr 0.8 La 0.2 Fe 12 O 19 sample sintered at 1200 °C possesses the maximum value of 60 emu/g.