Structural, optical, and dielectric investigations in bulk PrCrO3

Abstract

The polycrystalline powder samples of PrCrO3 have been prepared using conventional solid-state synthesis method. Structural investigations are carried out using Raman spectroscopy and synchrotron X-ray diffraction (SXRD) followed by Rietveld refinement of diffraction data. Investigations of diffraction data suggest that these samples possess centrosymmetric orthorhombic structure with space group Pnma(orPbnm). The valence (charge) state of Cr in PrCrO3 has been determined from X-ray absorption near edge spectroscopy (XANES). Optical properties are studied using diffuse reflectance spectroscopy technique. Optical absorption study reveals that absorption in PrCrO3 ceramic is dominated by d–d electrons of chromium cation (Cr3+). The synthesized compound found to have energy bandgap of 3.20 eV. Based on the results observed, energy level diagram for PrCrO3 has been presented. High dielectric permittivity (ε′) of the order 3 × 10 3 is observed for the studied sample. Impedance spectroscopy measurement at room temperature on sintered pellet indicates electronic inhomogeneity in the samples as demonstrated by the presence of dielectric relaxation processes associated with highly conducting grain and low conducting grain boundaries. The relaxation mechanism has been explained on the basis of Cole–Cole model. Observed high dielectric permittivity (ε′) and optical energy bandgap (Eg) indicates that PrCrO3 may find promising application in optoelectronic devices. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.