Up-scalable fabrication of nanosized nickel cobalt chromite spinel by a simple thermal treatment method: Structural and paramagnetic behavior

Considering the simplicity and flexibility of thermal treatment method for preparing fine nanocrystalline oxide, the present work reports up-scalable synthesis of nanosized nickel cobalt chromite spinel. The effect of calcination temperatures on the final properties of obtained materials was carefully examined using various characterization techniques. The XRD and FT-IR spectra confirmed the formation of nickel cobalt chromite spinel phase in the calcination temperature of 550-850 degrees C. The estimated average sizes from TEM images increases from 10 nm at 550 degrees C to 51 nm at 850 degrees C, which are in good agreement with determined crystallite size from XRD analysis. The calcined samples at 650 and 850 degrees C showed paramagnetic behavior with g-factor of 1.93 and 2.19, peak-to-peak line-width of 2053 and 8905 A/m, and resonance magnetic field of 27089 and 23755 A/m, respectively. Variation in the value of g-factor, peak-to-peak line-width and resonance magnetic field may be attributed to the dipole dipole and super exchange interactions.