Structural and tunable dielectric properties of cobalt ferrite-based nanocomposites

Abstract

Nanocomposites C:S-1:4 comprising cobalt ferrite (CoFe2O4), strontium ferrite (SrFe12O19) and C:B-1:4 containing cobalt ferrite (CoFe2O4), barium ferrite (BaFe12O19) were synthesized in weight ratios of 1:4 by chemical co-precipitation route with higher content corresponding to SrFe12O19 and BaFe12O19. Rietveld refinement was employed to confirm the presence of independent CoFe2O4, SrFe12O19 and BaFe12O19 phases. The average crystallite size of CoFe2O4 and SrFe12O19 in C:S-1:4 was observed as 20 nm and 56 nm which depicts an increase as compared to individual components. The observed lattice strain in C:S-1:4 was 0.05% and 0.03% for CoFe2O4 and SrFe12O19. In C:B-1:4, the value of strain was 0.06% and 0.04% for CoFe2O4 and BaFe12O19. Increased lattice strain was observed in the prepared composites. Increase in impedance for the prepared composites was observed from measurements performed in the frequency range 20 –106 Hz. Conduction mechanism was explained by overlapping large polaron tunneling model. Dielectric loss measurements for the prepared composites were observed to decrease establishing their usage in microwave applications.