Moessbauer Study of Microstructure and Magnetic Properties (Co, Ni)-Zr Substituted Ba Fertile Particles

摘要

The barium hexaferrites of M-type BaFe_(12-2x)(Co, Ni)_xZr_xO_(19) were synthesized by citrate precursor method in 0.0 ≤ x ≤ 0.6 range. For comparison, Ni-Zr compounds were also prepared by mechanical milling. Moessbauer measurements show that of Zr~(4+) ions have preference for 2b and 2a+4f_1 sites whereas Co~(2+) ions prefer 4f_2 and 12k positions. Different occupations were observed on Ni-Zr substitutions. The temperature coefficient of the coercivity, dH_c/dT, was nearby to zero (0.01 kA/m°C) for the Co-Zr substitutes and positive for the rest of the samples. A fast reduction of coercivity H_c with the increase in substitution level (370 to 150 kA/m) were underwent for all (Co, Ni)-Zr mixtures.