Investigation of Magnetic Properties of Zn Doped Y-Type Barium Ferrite

The Ba2Co2-xZnxFe12O22 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) polycrystalline samples were synthesized by the solid- state reaction method. Based on the Rietveld refinement, the crystal structures of samples were found to be single- phased and determined to be rhombohedral with space group of R - 3m. The unit cell volume (V-u) of the samples increased with increasing Zn ion concentration. In the magnetic phase diagram of Ba2Co2-xZnxFe12O22 system, samples with x <= 1.5 showed the spin transitions both at T-s and T-c. For x = 2.0 sample, we observed the disappearance T-s. The non-magnetic Zn ions preferentially occupy the tetrahedral sublattices of 6c(IV), and 6c*(IV) with down-spin site. At low temperature, this leads to the increase in M-s. However, the experimentally measured M-s at 295 K shows a slight decrease around x = 1.5. In addition, we have measured Mossbauer spectra of samples at various temperatures ranging from 4.2 to 750 K, which can analyzed with six-sextets for Fe sites corresponding to the 3b(VI), 6c*(IV,) 6c(VI), 18h(VI), 6c(IV), and 3a(VI) of the Y-type hexagonal crystallographic sites. From the Mossbauer spectra of 295 K, we observed the line-width broadening with increasing Zn concentration.