Danchevskaya M.N. , Ivakin Yu.D. , Martynova L.F. , Muravieva G.P.
High Pressure Research (in the press)
Abstract. The authors of the report carried out synthesis of barium hexaferrite (BHF) both in water vapor atmosphere and in liquid medium in the temperature range 200-400 C at pressures PЅ2o of 9-26 ЬP in laboratory autoclaves. The results of results have shown that BHF with the best performances can be obtained by thermovaporous treatment of dry mixtures of precursors gamma-Fe2O3 with barium hydroxide or nitrate). As Fe - containing precursor,alfa-FeOOH can be also used. The formation of BHF begins at the temperature of about 200 ±. The BHF crystals are hexagonal platelets with diameter less 1 mkm and thickness 0,1-0,2 mkm. The magnetic properties of synthesized BHF can be improved by increasing the temperature of thermovapor treatment. The coercive forces of the BHF samples synthesized at about 400 C vary from 1.7-2.0 kOe and specific saturation magnetization of nonoriented samples from 40-50 emu/g. BHF crystals with low coercive force (0.6-0.7) kOe were obtained by introduction of doping microadditives at the stage of their formation in water vapor atmosphere.