Effect of magnetic ion substitution on the structure and temperature-dependent magnetic properties of strontium hexaferrite

Rare earth substituted strontium hexaferrite powders were synthesised through a molten salt route at 900°C for 5 h. The influence of rare-earth magnetic ion substitution on microstructural features, morphology and temperature-dependent magnetic properties was investigated. The lattice parameter ratio of less than 3.98 proves that all the substituted samples primarily present the hexaferrite phase. Fourier transform infrared peaks also confirmed the presence of a metal-oxygen bond. A 66% increase in magnetic saturation, 38% increase in coercivity and a more than two-time increase in remanence for the samarium doped sample are seen as the highest magnetic measurements compared to pure SrFe12O19 at room temperature. There were also differences in the temperature-dependent magnetic properties of strontium ferrites. As temperature decreased from 300 K, saturation magnetisation and remanence value were found to increase. This will perhaps be a promising material for magnetic field sensor application.