Synthesis of non-magnetic-ion-substituted Ca-based M-type ferrite

抄録

  We investigated the synthesis conditions and magnetic properties of non-magnetic-ion-substituted Ca-based hexagonal ferrites, Ca_0.8La_0.2Fe_8.0−2xMg_xTi_xO_19−σ (x = 0.1–3.5) and Ca_0.8La_0.2Fe_y−xAl_xO_19−σ (x = 1.0–5.0, y = 8.0–10). We found that Mg-Ti-substituted Ca-based M-type ferrites formed at x = 0.1 and 0.2 at above 1225ºC. The sample at x = 0.1 showed the crystallographic single phase of M-type ferrite. The minimum Curie temperature of the Mg-Ti-substituted samples was 367ºC. Also, we found that the Al-substituted Ca-based M-type ferrites had the main phase of M-type ferrite in all samples. As the amount of substituted Al increased, the saturation magnetization and the Curie temperature decreased, and the coercivity increased. As the amount of substituted Al increased by Δx = 1, the Curie temperature decreased by ΔT_C = 50–70ºC. Al-substituted samples of x = 1.0 and 2.0 sintered at 1300ºC had the single phase of M-type ferrite.