Effect of Sr-substitution on the structural and dielectric properties of LaFeO₃ perovskite materials

Abstract

The study aims to investigate the structural and dielectric properties of perovskite La 1Àx Sr x FeO 3 (x ¼ 0:1, 0.2, 0.3, and 0.4) synthesized by sol-gel and sintering methods. X-ray diffraction (XRD), transmission electron microscopy (TEM), and LCR-Meter were used to identify the phase, crystallography parameters, morphology, particle size, and electrical behavior of the synthesized perovskite materials. The samples showed a single-phase orthorhombic crystal structure with Pbnm space group. Sr-substitution induced the volume unit cell and crystallite size to decrease. The synthesized nanoparticles were uniform and homogeneous with the particle size less than 200 nm. Impedance spectroscopy (IS) was used to explain the electrical behavior as a function of frequency (100 Hz to 1 MHz) at various temperatures (300-373 K). The presence of small polarons as charge carriers within the grain and grain boundary were elucidated from the electrical conductivity experiments. Sr-substitution caused the dielectric constant and electronic conductivity to increase with the highest values obtained from La 1Àx Sr x FeO 3 (x ¼ 0:4).