Structural and Magnetic Properties of BaFe12-xAlxO19Prepared by Milling and Calcination

Abstract

Al substituted barium ferrite particles BaFe_12-xAl_xO₁₉ with 0 ≤ x  ≤ 0.8 have been prepared by ball milling method. X-ray diffraction (XRD) has shown that the average crystallite size for all samples under investigation is in the range 66 – 76 nm. Scanning electron microscopy (SEM) imaging indicates that the particle size is in the range 0.2 – 1.0µm, which demonstrates that the particles are polycrystalline. It was found that Al substitution does not significantly change the particle size of BaFe_12-xAl_xO₁₉. The magnetic properties have been investigated using a vibrating sample magnetometer, and the anisotropy field is estimated. It was found thatthe coercivity of the samples increases from 4.2 kOe to 6.0 kOe with increasing Al concentration from x= 0.0 to 0.8 due to the increase in the anisotropy field. Interparticle interactions determined from the remnant magnetization data are found to be consistentwith a reversal mechanism (demagnetizing like effect) for all samples examined.

Keywords: Ball milling; Barium ferrite; Coercive field; Magnetization.