In this study, the frequency and temperature dependent dielectric relaxation and electrical conduction mechanisms in NiAl2O4 spinel oxide ceramic have been explored in a frequency range of 50-10x106 Hz over a measured temperature from 163-283 K. The polycrystalline NiAl2O4 was synthesized via solid state reaction route and sintered at 1000 °C. The room temperature X-ray powder diffraction pattern confirmed the formation of NiAl2O4 spinel phase with Fd3m space group. The surface morphology of the sample was investigated by scanning electron microscopy and chemical properties by Fourier transform infrared spectroscopic analysis. Complex impedance studies revealed the presence of relaxation time distribution and charge carriers were found to be thermally activated. The Nyquist plots exhibited depressed semicircles and their fitting by an equivalent circuit model with configuration (RGCG)(RGBCGB) resolved the contributions of grains and grain boundaries to the electrical transport properties of the material. Electrical conductivity analysis followed the Jonscher’s power law behavior and the frequency exponent suggested small polaron hopping as the governing transport mechanism in NiAl2O4 spinel oxide. Non-Debye type nature of dielectric relaxation was confirmed by the complex modulus analysis whereas dielectric constant and tangent loss analysis verified that the hopping mechanism was thermally activated.

In this work, modification in structural and electrical properties of zirconium nitride (ZrN) thin films induced by silicon-ion irradiation is studied. ZrN thin films are grown on glass substrate over Zirconium (Zr) layer using cathodic arc evaporation method. The samples of the film are irradiated with silicon ions of energy 2.08 MeV at different fluences ranging from [Formula: see text] ions/cm[Formula: see text] to [Formula: see text] ions/cm[Formula: see text]. The structural and electrical properties of the prepared films are investigated using X-ray diffraction (XRD), Raman spectroscopy and four-point probe method. XRD analysis shows significant shift in the peak corresponding to (111) crystallographic plane of ZrN at low fluence ([Formula: see text] ions/cm[Formula: see text]) while modest peak shift at high fluence rate ([Formula: see text] ions/cm[Formula: see text]) is observed. Under the electrical properties point of view, it is observed that the decrease in resistivity is small at high ion fluence as compared to that at low ion fluence. At highest fluence of [Formula: see text] ions/cm[Formula: see text], resistivity of the irradiated sample approaches the resistivity of the un-irradiated sample indicating very small changes in structure at very high dose irradiance.

Silicon nitride thin films have numerous applications in microelectronics and optoelectronics fields due to their unique properties. In this work, silicon nitride thin films were produced using radio frequency (R.F.) magnetron sputtering technique at various sputtering powers. The prepared thin films were characterized with XRD, FE-SEM, FTIR, surface profiler, AFM and spectral reflectance techniques for structure, surface morphology, chemical bonding information, growth rate, surface roughness and optical properties. The results showed that silicon nitride thin films were amorphous in nature. The films were smooth and densely packed with no voids or cracks at the surface. FTIR characterization informed about Si-N bonding existence which confirmed the formation of silicon nitride films. The sputtering power showed the impetus effect on growth rate, surface roughness and optical properties of produced films.