Crystal structure and magnetic properties study on barium hexaferrite of different average crystallite size.

Barium hexaferrite (BHF) is a promising material for technological applications. Hence, the large production of BHF for industrial application needs attention. Therefore, the effect of annealing temperature on the crystal structure, morphology, and magnetic properties of barium hexaferrite has been explored in this article. The BaFe12O19 (BHF) was prepared by the sol–gel method and annealed at different temperatures (800 °C, 900 °C, 1000 °C, and 1100 °C). The crystal structure of BHF is investigated by the Rietveld refinement of XRD patterns using Fullprof suit software. Bond lengths and bond angles have been calculated using the Rietveld refined crystal structure parameters. The FESEM micrograph reveals the cylindrical shape of BHF particles for the samples annealed above 900 °C. Large average grain size has been observed for 1100 °C annealed BHF sample. The average crystallite size (obtained from XRD analysis) and particle size (obtained from FESEM) increase with an increase in annealing temperature of BHF. It is observed that the magnetic properties of BHF depend on bond angles and bond lengths between Fe and O atoms at different crystallographic sites. The saturation magnetization and coercivity are found to increase with the increase in average crystallite or particle size, but the variation is very small. [ABSTRACT FROM AUTHOR]