Defect mediated magnetocapacitance effect in NiO investigated with thermoluminescence effect

The origin of magnetocapacitance effect in NiO prepared using solution combustion method was explored in this work. The structural analysis of NiO powder showed formation of pure phase. The change in capacitance with applied magnetic field was of the order of 6.5 % at 1.2 MHz. The positive sign of magnetocapacitance inferred that the process is interface mediated and supported by diminished magnetoresistance at the same frequency. The origin of this interface effect was explored using thermoluminescence study. The deconvolution of glow curve inferred formation of deep level defects with the number density of the order of 8.46 x 104 and activation energy or formation energy of 1.4 eV. The presence of deep level defects corroborated the observation of positive magnetocapacitance in NiO supporting the defect mediated change in capacitance.