Charge conduction mechanism and non-debye type relaxation in LaCrO3 perovskite orthochromite

Abstract

The orthochromite LaCrO3 (LCO) was synthesized via the sol-gel auto-combustion route and sintered at 900 °C. The Rietveld refined XRD profile confirmed the single-phase perovskite structure of the compound crystallized in the orthorhombic unit cell with Pbnm space group symmetry. The electrical studies were conducted by complex impedance spectroscopy in 40-5 × 106 Hz and 133–363 K experimental ranges of frequency and temperature, respectively. The complex impedance data were modeled by (RGQG)(RGBQGB) equivalent circuit that revealed the contributions of grains and grain boundaries to the electrical transport mechanism of the material. The AC conductivity analysis proposed that the electrical conduction in the LCO perovskite was governed through Mott's variable range hopping (VRH) mechanism. The imaginary modulus spectra were fitted by the Kohlrausch–Williams–Watts (KWW) relaxation function that resolved the presence of two thermally activated relaxation phenomena. The dielectric permittivity followed the non-Debye relaxation model which characterized the nature of dielectric relaxation in the LCO chromite.