Enhanced electrical and magnetic properties of CuO/MgO nanocomposites

Highlights: • CuO/MgO nanocomposite prepared by the sol-gel method were analyzed. • The dielectric properties of CuO/MgO nanocomposite were studied in detail at different temperatures. • The electrical properties of CuO/MgO nanocomposite were also discussed. • Magnetic properties are analyzed using Vibrating Sample Magnetometer (VSM) The present work deals with the synthesis, characterization, and testing of copper oxide (CuO)/magnesium oxide (MgO) nanocomposites formed with two different ratios. The composites formed by the sol-gel synthesis route were thoroughly characterized for physicochemical properties like powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), dielectric, and magnetic behavior. From the powdered XRD analysis, the synthesized composites were found to be associated with high crystallinity, where the monoclinic phase was noted for the cupric oxide while the cubic phase for magnesium oxide, in addition to the measurement of crystallite sizes by Scherer formula. The FESEM and FTIR analysis provided the surface morphology and functional groups present at the surface of CuO/MgO nanocomposite. Further, the nanocomposite's dielectric behavior and impedance properties were studied in the frequency range of 100 Hz–5 MHz at different temperatures (308–563 K). The complex impedance spectra show the negative temperature coefficient of resistance (NTCR) behavior of synthesized nanocomposites and further it is confirmed with electric modulus spectra. The AC conductivity increases with increasing frequency which obeys the Jonscher's universal power law ${\sigma }_{\mathrm{AC}}\left(\omega \right)=A{\omega }^s$, the values of frequency exponent (s) > 1, indicates that the motion involves the localization or reorientation hopping and is assisted by a large polaronic mechanism among the neighboring sites. Finally, the studies of magnetic behavior by making use of a vibrating sample magnetometer (VSM) indicated the presence of a small hysteresis loop for the CuO/MgO nanocomposite at room temperature.