Abstract: 

Nickel Oxide (NiO) nanoparticles (NP) with co-doping of different concentrations (maximum 6%) of Manganese (Mn) and cobalt (Co) were prepared by Composite hydroxide method (CHM). X-ray diffraction pattern confirms the formation of cubic structure of NiO NPs and no extra peak was observed. The average crystallite size was obtained from XRD and found to be 15-17.8 nm with the varying concentration of Mn and Co. The SEM images showed that the nanoparticles were almost spherical and agglomerated due to their magnetic nature. Fourier transform infrared spectroscopy analysis confirmed the existence of Mn and Co co-doped NiO which indicates the dispersion or substitution of the dopant material in the host material which were proved from XRD results. The imaginary part of dielectric shows a decreasing trend with the increase in frequency because it is harder for electrons to align themselves along the direction of the field at higher frequency. The both real and imaginary parts of dielectric constant showed an increasing trend at lower frequency and decreasing trend at the higher frequency in agreement with Koop's theory. The dielectric loss is due to the flipping of dipoles and migration of charge carriers from grains to grain boundaries. Ac conductivity showed an increasing trend at higher frequency and decreasing at lower frequency due to the contribution of grain and grain boundaries. These properties make them suitable for energy conversion devices like solid oxide fuel cells and supercapacitors.

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