Structural, optical, morphological and magnetic properties of nickel doped cobalt ferrite nanoparticles synthesized by hydrothermal method

The nickel substituted cobalt ferrite (Ni_xCo_1−xFe₂O₄) nanoparticles were synthesized by using simple hydrothermal method. The cubic spinel structure was confirmed by X-ray diffraction pattern. The crystallite size calculated using Debye Scherer formula were in the range 10.91 to 16.76 nm and 10.02 to 43.82 nm for x = 0.0 and 0.3, respectively. A little agglomerated morphology of particles was observed from SEM. The HR-TEM visualized the cubic shape of the synthesized nanoparticles (NPs). The shifting of bands related to Fe–O and Ni/Co–O were noticed in FT-IR spectra towards the higher wavenumbers for the annealed samples. The peak shift in Raman study was due to the cation redistribution, while doping and annealing. The annealed samples showed the decreased optical band gap compared to as synthesized one. The Mossbauer spectra revealed the contribution of cations among the tetrahedral and octahedral sites. The ratio of M_r/M_s confirmed the nature of single domain stage in the synthesized sample. The CV curve revealed the Pseudocapacitive behaviour. Specific capacitance value (C_s) was low at high scan rate and high at low scan rate.