Preparation of Magnetopulmbite Type Ferrite Thin Films by Dip-Coating Method and Magnetic Properties

Abstract

Thins film of magnetoplumbite type ferrite (MFe12O19, M=Ba, Sr) have been prepared by the dip-coating method from solgel process. Ferric nitrates, other metal nitrate and titaniumoxiacetylacetonate were used as law materials, and glycerol was used as solvent. A film was prepared by dipping a silica glass plate. The magnetoplumbite type ferrite was obtained by heattreatment at 750°C for 5h in air. The film thickness was about 0.08μm. The coercive forces (Hc) of the film and powder with the composition of 15BaO⋅85Fe2O3 was 3300 and 3050 Oe by heat-treatment at 850°C for 48h respectively. These films were shown to have much larger Hc than the powder. The effect of substitution of titanium and cobalt ion in barium hexaferrite films and powders were investigated. The saturation magnetization of the powder in the system 15BaO⋅85 [(100-2x) Fe2O3⋅xTiO2⋅xCoO] was almost constant in the range of 0≤x≤8.33. But the Hc changed drastically with increasing titanium and cobalt ion content. The Hc of the powder was controllable in the range of 50 Oe and 3050 Oe by changing the substitution contents for the same system. The Hc of the films was controllable in the range of 300 Oe and 3300 Oe for the same system.