Correlation between site preference and magnetic properties of Co-Zr doped BaCo_xZr_xFe_(12-2x)O_(19) prepared under sol-gel and citrate precursor sol-gel conditions

摘要

Herein, we report the synthesis of Co-Zr doped BaCo_xZr_xFe_(12-2x)O_(19) (x = 0.0, 0.2,0.4, 0.6, 0.8, and 1.0) M-type hexagonal ferrites under sol-gel (series 1) and citrate precursor sol-gel (series 2) conditions. These compounds were characterized by TG-DTA, FT-IR, XRD, EDS and BET techniques. XRD patterns and parameters reflect that series 2 yield more symmetrical structures with lower average particle size. Results reveal that magnetization and magnetocrystalline anisotropy are closely related to the distribution of Co-Zr on the five sub lattices. The compounds of series 1 register a steep fall in coercivity [5428 Oe (x = 0) to 630.2 Oe (x= 1.0) than series 2 [2790 Oe (x = 0) to 1210 Oe (x = 1.0)]. M_s varies from 63.63 to 56.94 emu/g and 62.79-53.78 emu/g in series 1 and 2, respectively. Mossbauer analysis suggests that site preferences strongly depend upon the nature of dopant, fuel and the preparatory conditions.