Structural, electrical, and optical features of Bi2FeCrO6 and Bi1.8La0.2FeCrO6 double perovskites for device applications

By surpassing single perovskites, double perovskites without any sort of Lead content are applicable as materials for solar and related applications due to their more stable nature, good catalytic efficiency, and negligible toxicity. So as to investigate the structural, electrical, and other diverse aspects of the Bi2FeCrO6 and Bi1.8La0.2FeCrO6 materials, we have synthesised them using a traditional solid-state reaction technique. By performing X-ray diffraction study, the crystal structures for both the samples are found to be monoclinic. The sample’s strain and crystallite sizes were extracted using the Williamson-Hall formalism. Molecular bonding and metal oxide vibrations like Bi–O and Fe–O were analysed via Fourier transform infrared (FTIR) spectroscopy. To further verify crystal structure and optical phonon modes, Raman spectroscopy has been performed. The surface analysis of the samples recorded by FESEM reveals that the small grains are allocated homogeneously through distinctive grain barrier. Diffuse reflectance spectroscopy revealed narrow band gaps for both samples which makes them suitable for photo-catalytic actions. The extracted valence band maximum (VBM) levels of the samples are in the domain of O2 evolution criteria. Along with the Urbach energy, refractive indices were also calculated in optical studies. For electrical study, dielectric characteristics of the compounds were analysed over a large temperature series. The thermal variation of the frequency exponent (n) obtained from the fitting of Jonscher’s rule verified the existence of the correlated barrier hopping conduction method. From impedance spectroscopy, negative temperature coefficients of resistance (NTCR) response in addition to non-Debye type of relaxation were noted. DC conductivity experiments provide the activation energy of the materials. Thermistor applicability for samples shows promising results. Ferroelectricity has been confirmed for both the samples.