化学的共沈法による(Sr・Ba)-La-Co系M型フェライト微粒子の磁気特性

抄録

(Sr⋅Ba)-La-Co M-type ferrite fine particles were prepared by the chemical coprecipitation and subsequent heat-treatment method. The chemical reagents used for the experiment were FeCl₃⋅6H₂O, BaCl₂⋅6H₂O, SrCl₂.6H₂O, LaCl₃⋅7H₂O, and CoCl₂.6H₂O. The chemical coprecipitation process was applied to the samples having the formula. {(SrO)₁-x⋅(BaO)x⋅n/2(Fe₂O₃)}_100-Y-Z(La₂O₃)_Y(CoO)_Z (n=6.0-12.0, x=0.0-1.0, y=1.0-10.0, z=1.0-10.0). The solution containing Sr²⁺, Ba²⁺, Fe³⁺, La³⁺, and Cot²⁺ was poured into solution of NaOH (pH=13.0). The precipitated products were boiled for 2h and they were carefully washed with water and dried. The obtained fine particles were heated at 950 to 1100°C for 2h in air to obtain the single phase of (Sr⋅Ba)-La-Co M-type ferrite fine particles. The best magnetic properties were observed for the sample with the composition of {(SrO)_0.8⋅(BaO)_0.2⋅3.5(Fe₂O₃)} _88.0 (La₂O₃)_6.0(CoO)_6.0, and magnetic properties were as follows: σ_s= 84.8 × 10^-6 Wb⋅m/kg (67.5 emu/g), σ_r=42.8 × 10^-6 Wb⋅m/kg (34.1 emu/g), H_cJ=476.6 kA/m (5.98 kOe) and Tc=452.6°C.