Structural, dielectric, optical and electronic properties of NdFeO₃ : experimental and computational study

Nanocrystalline NdFeO₃ was synthesized via a sol–gel route. The structural and morphological study was achieved by X-ray diffraction, transmission electron microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM). The Rietveld refinement of the X-ray diffraction pattern showed a single orthorhombic phase with the Pbnm space group. The average crystallite size was about 44 nm. The electrical behavior of the as-prepared sample was investigated in a frequency range of 0.1 Hz − 1 MHz at different temperatures. We showed that the dielectric response is of the non-Debye type. Impedance spectroscopy confirmed that DC conductivity could be described by Mott’s VRH (variable range hopping) model at 298–423 K temperature range. In addition, the hopping distance (Rhop) decreases as the hopping energy (Whop) increases, leading to an overall increase in electrical conductivity. The UV–Vis absorption spectra measured at room temperature showed a strong absorption in the ultraviolet range (200–400 nm). From the Tauc plot, the band gap was estimated to be 2.58 eV. DFT calculations were also achieved with generalized gradient approximation (GGA + U) using Wien2k code. The electronic band structure and the DOS calculation were investigated. We found a sensible agreement between the experimental results and the calculated ones.