Synthesis and Characterisation of Copper Substituted Cobalt Ferrite Nanoparticles by Sol-Gel Auto Combustion Route

In the present study, the structural, functional, morphological and magnetic characteristics of copper substituted cobalt ferrite nanoparticles were investigated. The samples of Co_1-xCu_xFe₂O₄ at x = 0.06, 0.08 and 0.1 M were prepared by Sol-gel auto combustion route. X-ray diffraction technique was used to confirm the phase formation and structural analysis which matches with the JCPDS Data. The average crystallite size was found to be ∼25, ∼19 and ∼18 nm for x = 0.06, 0.08 and 0.1 respectively. The Micro Raman Spectroscopy revealed the stretching vibrations at 274 cm⁻¹, 660 cm⁻¹, and 466 cm⁻¹, which are characteristic of Spinel Ferrites. From the FTIR analysis, the band observed at 3457cm⁻¹ and 1650 cm⁻¹ is assigned to hydrogen bonded O-H group and ionic stretching of C-H bond. The band assigned at 1105 cm⁻¹, is due to Co – O and Cu - O or Fe – O vibrations. The existence of water adsorption band and metal oxygen band confirms the existence of Co and Cu in the synthesized sample. The surface morphology of samples was imaged by the field emission scanning electron microscope. The substitution of Cu²⁺ in the parent systems caused a significant reduction in particle size. The compositional analysis was done, which confirmed that the concentration of copper was increased in the samples. The samples were subjected to magnetic characterization because magnetic behavior is also affected by substitution of Copper in Cobalt ferrite. Magnetic hysteresis study at room temperature confirmed the reduction in saturation magnetization (M_S = 14.25 to 8.33 emu/g.) and reduction in coercivity (H_C = 602.64 to 380.94 Oe) when size is reduced. As the concentration of Cu into CoFe₂O₄ matrix increases, particle size decreases and the saturation magnetization decreases.