Structural and magnetic properties characterization of mechanically alloyed la substituted Ba_(1-x)La_xFe₁₂O₁₉ (x = 0.07, 0.15 and 0.20)

This study reported the structural studies and magnetic properties of La-substituted barium hexaferrite (BHF) with Ba_1-xLa_xFe₁₂O₁₉ (x=0. 07, 0.15 and 0.20) constitutions. All samples were synthesized through mechanical alloying technique using BaCO3, La2O3 and Fe2O3precursors that were mechanically milled for 20 hours and successively sintered at 1200 °C to produce polycrystalline materials. The X-ray diffraction (XRD) method was employed to characterize the microstructure of synthesized materials. Structural analysis by refinement of XRD data showed that all sintered Ba_1-xLa_xFe₁₂O₁₉ (x=0.07, 0.15 and 0.20) samples are single phase material. The crystallite size of all samples was below 150 nm, with the mean size value decreased from 35 nm in sample of x = 0.07 to 23 nm in x = 0.20. This was accompanied by a change in crystallite size distribution toward the slim distribution. Magnetic properties characterization of La substituted BHF showed a substantial increase of coercivity as the fraction of La increased but the remanent magnetization decreased.The largest coercivity value of 315 kA/m was obtained in sample with x = 0.20 which is almost double when compared with low substitution of La (x = 0.07).