Structural and magnetic property modification of strontium hexaferrite system using A-site Ca doping
摘要
Ca-doped strontium (Sr1-xCaxFe12O19, x = 0.10–0.50) hexaferrite samples were synthesized following the solid-state reaction route. Absence of secondary phases in X-ray data points to a maximum value of Ca solubility in SrM ≈ 50% (at 1200 °C). The doped samples develop preferred orientations (along (006) and (008) crystallographic planes) at highest Ca doping (x = 0.50). XRD confirmed a reduction in `c’ parameter from 23.036 Å to 23.016 Å with variation in x from 0.10–0.50. FESEM micrographs reveal an enhancement in sample density and an increase in the average grain size (≈1.35 μm at x = 0.10 to ≈1.83 μm at x = 0.50). Ms value is maximum (≈ 79.56 emu/g) at x = 0.10 whereas Mr value is maximum (≈ 53.31 emu/g) at x = 0.50. The observed Ms value is the highest amongst the literature reported values for doped and undoped SrM samples. The coercivity decreases from 5032 Oe (at x = 0.00) to 2561 Oe (at x = 0.50).