Change of Structure and Magnetic Properties of La-Substituted Barium Hexaferrite

The substitution of Lanthanum into barium hexaferrite (Ba_1-xLa_xFe₁₂O₁₉) for La³⁺ (x = 0, 0.2, 0.4, and 0.6) has been synthesized using the solid reaction method through mechanical milling. Refinement results from X-ray diffraction patterns (XRD) showed that the formation of hexagonal crystal structures with space group P63/mmc, where the lattice parameters of a = b and c decreased, while the lattice strain obtained increased with increasing La concentration in the sample. The single phase is obtained at the concentration of x = 0, while the concentration of x = 0.2, 0.4 and 0.6 are already multi-phase. The morphological observation of particles using a scanning electron microscope (SEM) shows that with the presence of the La³⁺ substitution results the particle size distribution varies. Saturation magnetization and magnetocrystalline anisotropy are reduced due to this La substitution. This is thought to be caused by a decrease in magnetic (Fe-O-Fe) interaction and a reduction in the barium hexaferrite phase fraction in the sample. It was concluded that the effect of La substitution on Ba_1-xLa_xFe₁₂O₁₉ resulted in changes in Crystal structure parameters, particle size distribution, and magnetic properties of the material. (paper)