Synthesis and characterization of high coercivity rare-earth ion doped Sr0.9RE0.1Fe10Al2O19 (RE: Y, La, Ce, Pr, Nd, Sm, and Gd)

► The study reports synthesis and characterization of rare-earth doped Sr0.9RE0.1Fe10Al2O19. ► Synthesis of pure phase rare-earth doped Sr0.9RE0.1Fe10Al2O19 using autocombustion method is reported. ► The coercivity and Curie temperature was found to be rare-earth ion anisotropy dependent. Highest values of coercivity and Curie temperature was observed for Pr ion doped samples as Pr ions has high anisotropy. ► The magnetization decreased with doping rare-earth ions with decreasing ionic radii. ► The grain size was observed to be rare-earth ion’s ionic radii dependent. Influence of replacing Sr2+ ions by rare-earth ions (RE3+) ions on the structural and magnetic properties of high coercivity (Hc) SrFe10Al2O19 hexaferrite have been investigated using X-ray diffraction, transmission electron microscopy, differential scanning calorimeter, and SQUID. A 73% increase in intrinsic coercivity is observed for Al3+ doped SrFe10Al2O19 as compared to that of pure SrFe12O19. The RE3+ doping brings in further 50% increase in the coercivity to Sr0.9RE0.1FeAll2O19. Overall the Curie temperature of Sr0.9RE0.1Fe10Al2O19 reduced upon RE3+ substitution, however, among rare-earth ions Pr3+ doping showed highest Tc∼620K. Doping SrFe10Al2O19 with RE3+ ions seems to be detrimental to the saturation magnetization but was observed to be favorable to the coercivity enhancement.