Rietveld Structure Refinement and Effect of Sintering Temperature on Elastic Properties of Cobalt Nano Ferrite

Cobalt ferrite nanoparticles were synthesized by citrate sol-gel auto combustion technique and sintered at 400 °C, 700 °C, and 900 °C. The structural characterization of the samples was done by using XRD, SEM and FTIR. The XRD and FTIR analysis clearly showed the formation of a cubic spinel structure for all samples sintered at different temperatures. The crystallite size increased from 15.99 nm to 69.08 nm while the grain size increased from 56.28 nm to 107.54 nm with increase in sintering temperature. It was observed that lattice parameters increase with an increase in sintering temperature. From the FTIR spectra, the higher frequency band in the range of 500-600 cm⁻¹ confirmed the vibrations due to M-O stretching at the tetrahedral site, while the lower band in the range 400-500 cm⁻¹ confirmed the vibrations due to M-O stretching at the octahedral site. In the present work force constants (K_t,K_0), elastic velocities (V_l,V_t,V_m), elastic moduli (Y,G,B), Poisson’s ratio, and Debye temperature were evaluated.