Influence of the Substitution of Iron by Aluminum and Titanium on the Structure and Properties of Barium Hexaferrite

Ionic substitution is considered to be an effective approach to modify functional characteristics of hexagonal ferrites. To this aim, solid solutions with iso- and aliovalent substitution of iron by aluminum and titanium, respectively, are prepared by the solid-phase synthesis. The influence of the Al³⁺–Ti⁴⁺ substitution on the structure and properties of BaFe_12–xAl_xO₁₉, BaFe_12–yTi_yO₁₉ is studied. The prepared solid solutions are studied by scanning electron microscopy and X-ray microanalysis, powder XRD, vibration magnetometry, and differential scanning calorimetry. The crystal structure data confirm that the synthesized samples are characterized by the hexagonal phase, the P63/mmc space group. The samples are shown to consist of 1-10 µm flat hexagonal crystals. The influence of substitution on their magnetic properties is determined. The substitution of Fe³⁺ magnetic ions by Al³⁺ and Ti⁴⁺ ions decreased the Curie point of the solid solutions. Since magnetic characteristics can be tuned by introducing Al³⁺ and Ti⁴⁺, this effect can be used to control the optimization of magnetic characteristics in BaFe_12–xAl_xO₁₉, BaFe_12–yTi_yO₁₉ solutions to solve applied problems.