Structural, electrical, dielectric and magnetic properties of Gd-Sn substituted Sr-hexaferrite synthesized by sol-gel combustion method

The effect of Gd-Sn substitution on the structural, electrical and magnetic properties of Sr1−xGdx Fe12−ySny O19 (where x=0.00, 0.025, 0.05, 0.075, 0.1) and (y=0.00, 0.25, 0.5, 0.75, 1) prepared by the sol-gel combustion method has been investigated. The XRD analysis shows the presence of Fe2O3 phase at higher substitution. The average crystallite size obtained lies between 19-42 nm which is beneficial in obtaining suitable signal-to-noise ratio in high density recording media. The FTIR spectra of annealed samples of SrFe12O19, Sr0.95Gd0.05 Fe11.5Sn0.5O19 show that strontium hexaferrite nanoparticles have been synthesized successfully. DC electrical resistivity shows metal-to-semiconductor transition with temperature. The value of transition temperature increases with dopant content. Room temperature dc resistivity and energy of activation decreases while drift mobility increases on increasing the dopant concentration. The magnetic properties such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) decreases with increasing the dopant concentration.