Sonochemical synthesis, structural, electrical transport and magnetic properties of NiWO4 nanoparticles

Abstract

The NiWO4 nanoparticles are synthesized by the facile sonochemical method and characterized using various analytical techniques. The thermal stability and the crystallization temperature of the as-prepared NiWO4 were revealed using thermogravimetric and differential thermal analysis (TG/DTA). Phase purity and crystallinity of wolframite type monoclinic structure of NiWO4 nanoparticles were corroborated using the X-ray diffraction (XRD) analysis. Fourier transform infrared spectroscopy (FTIR) employed to understand the bending and stretching vibrations of the M–O bonds and the surface functional groups present in NiWO4. The average particle size of 25 nm with nearly spherical morphology of the NiWO4 nanoparticles was inferred using both scanning electron microscopic (SEM) and transmission electron microscopic (TEM) techniques. A comparative impedance spectral analysis was carried out at both room (300 K) and high temperature (973 K) to analyze the temperature-dependent conductance behaviour of NiWO4 nanoparticles. The negative temperature coefficient of resistance (NTCR) behaviour of NiWO4 nanoparticles was revealed through the decreasing resistance with increasing temperature and obtained the d.c. conductivity of 7.493 $$\times $$ 10−8 S cm−1 at 973 K. The hopping conduction mechanism and thermally activated mobility of charge carriers were observed in the present study. Further, the dielectric study infers the contributions of grain boundaries and grains at low and high frequencies, respectively. Finally, the room temperature paramagnetic behaviour of the NiWO4 is corroborated through vibrating sample magnetometer (VSM) analysis.