Influence of cation distribution on the magnetic and dielectric properties of Zn doped CFO ceramics

Cations site registry of Co1-xZnxFe2O4 (0 ≤ x ≤ 0.3) ceramics, synthesized by combustion method, has been estimated using Mossbauer spectroscopic study and Rietveld analysis and its influence on the magnetic and dielectric properties have been studied. Decreased B-site hyperfine field with progressive Zn doping due to the occupancy of non-magnetic Zn ions in the tetrahedral site of CFO lattice has been observed in Mössbauer data. Magnetic moment of Co1-xZnxFe2O4 (0 ≤ x ≤ 0.3) calculated from the cation distribution estimated from the Mössbauer data has been compared with the experimentally observed magnetic moment. Decreased dielectric constants (ε′) with increasing Zn concentrations, in the frequency range 20Hz - 1MHz (at ~300K), indicates increased Fe+3 concentrations in the octahedral sites. The temperature dependent dielectric data showed a progressive reduction in the magnetic transition temperature (TC) from 528˚C for x = 0 to 422˚C for x = 0.3 of the Co1-xZnxFe2O4 (0 ≤ x ≤ 0.3) samples. Increasing relaxor behavior (γ = 1.85 for x = 0 to γ = 2.2 for x = 0.3) has been observed with increasing Zn content in the CFO lattice.