Structural, optical and dielectric properties of Ni substituted NdFeO3

Present study reports the structural, optical and dielectric properties of Ni substituted NdFe1-xNixO3 (0 <= x <= 0.5) compounds prepared through the ceramic method. X-ray diffraction (XRD) confirmed an orthorhombic crystal structure of all the samples. Both unit cell volume and grain size were found to decrease with an increase in Ni concentration. Morphological study by Scanning electron microscope (SEM) shows less porosity with Ni substitution in present system. From UV-vis spectroscopy, the optical band gap was found to increase with Ni doping. This observed behavior was explained on the basis of reduction in crystallite size, unit cell volume and its impact on the crystal field potential of the system after Ni substitution. The dielectric properties (epsilon' and tan delta) as a function of frequency or temperature, and the ac electrical conductivity (sigma(ac)) as a function of frequency have been studied. Hopping of charge carriers between Fe2+ -> Fe3+ ions and Ni2+ -> Ni3+ ions are held responsible for both electrical and dielectric dispersion in the system. Wide optical band gap and a very high dielectric constant of these materials promote them to be a suitable candidate for memory based devices in electronic industry. (C) 2014 Elsevier GmbH. All rights reserved.