Structural properties and hyperfine interactions in Co-Zn Y-type hexaferrites prepared by sol-gel method

Y-type barium hexaferrites Ba2Co2−xZnxFe12O22 (0.0≤x≤2.0) were prepared using sol-gel method and then sintering at temperatures between 900 and 1100 °C. The properties of the prepared samples were investigated using X-ray diffraction, scanning electron microscopy, and Mössbauer spectroscopy. XRD patterns revealed the presence of a single Y-type hexaferrite phase in the samples sintered at temperatures above 1000 °C. Mössbauer data indicated that Co2+ ions occupied octahedral sites in the T blocks, while Zn2+ ions were distributed between the two tetrahedral sites. This trend for cationic distribution resulted in weakening the superexchange interactions between spin-up and spin-down sublattices with increasing Zn content, and a consequent reduction in the hyperfine fields in Zn rich compounds.