Electrical, dielectric and magnetic characterization of Bi-Cr substituted M-type strontium hexaferrite nanomaterials

Strontium hexaferrite nanoparticles substituted with bismuth and chromium having nominal composition SrFe12−2xBixCrxO19 (x=0.2, 0.4, 0.6, 0.8) have been synthesized by the sol-gel method. The samples are characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), DC electrical resistivity, magnetic and dielectric measurements. The XRD data shows that the nanoparticles are crystallized into single hexagonal magnetoplumbite phase. Room temperature DC electrical resistivity decreases on increasing the Bi-Cr contents. The dielectric constant, dielectric loss and tangent loss decrease with the frequency. The magnetic properties such as saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) increase with increasing the dopant concentration up to x=0.2 and then decrease with further increase in dopant content. Coercivity decreases with increasing the dopant content up to x=0.2 then increases with further increase in dopant content. The increase in Ms and Mr while decrease in Hc indicates that the material with composition SrBi0.2Cr0.2Fe11.6O19 is suitable for magnetic recording media.