First-principles and experimental study of structural, electronic, and enhanced dielectric response in Bi2Ca1.95Sm0.05CoO6 nanoparticles

In this study, we synthesized Bi2Ca1.95Sm0.05CoO6 (BCSCO) by the Co-precipitation route. X-ray diffraction was used for structural analysis, which confirmed the monoclinic structure with space group P21/m. Here, we employ the CASTEP (Cambridge Serial Total Energy Package) approach, we conducted a theoretical investigation of the structure, electronic, and optical properties of BCSCO double perovskites. FTIR spectra, BCSCO presents three absorption bands that correspond to the Bi(Ca)-O, O-Co-O, and Co-O. The morphological study showing the agglomeration phenomenon has occurred in the synthesized sample. The AC conductivity and dielectric response have also been studied as a function of frequency (100 Hz-3 MHz) at different temperatures (100 degrees C-600 degrees C). Temperature-dependent dielectric relaxation was investigated, and employing the non-linear Debye fitting to determine the spreading factor and relaxation time. The maximum value of the dielectric constant is 2.4 x 106 at 600 degrees C. AC conductivity is examined at (100 degrees C-600 degrees C) using Jonscher's power law. The model fitting shows the Overlapping Large Polaron Tunneling conduction mechanism for BCSCO. In order to explore the impact of grain barriers and interior, the Nyquist plot was utilized, and the results are inter-connected.