Research on La3+-Co2+-substituted strontium ferrite magnets for high intrinsic coercive force

Abstract M-type strontium ferrites with substitution of Sr 2+ by rare-earth La 3+ , and a little amount of Fe 3+ by Co 2+ according to the formula Sr 1− x La x Fe 12− x Co x O 19 , are prepared by the ceramic process. Effects of the substituted amount of La 3+ and Co 2+ on structure and magnetic properties of Sr 1− x La x Fe 12− x Co x O 19 compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and B–H hysteresis curve measurements. In our results, the suitable amount of La 3+ –Co 2+ substitution may remarkably increase saturation magnetization. Intrinsic coercive force ( H cj ) of Sr ferrite magnets is evidently increased without significant decrease in residual flux density ( B r ) by La 3+ –Co 2+ substitution.