Exploration of the structural, optical, and dielectric performance of Mg-doped Sr2FeNbO6 double perovskite for wireless applications

This study examined the effects of Mg doping on the structural, optical, photoluminescence, and dielectric properties of a series of double perovskite Sr_2-xMgₓFeNbO₆ (0.00 ≤ x ≤ 0.40) ceramics that is successfully manufactured by using the mixed oxide route. It was proven by X-ray diffraction that a single-phase monoclinic perovskite (space group P21/c.) had formed, and at increasing Mg concentrations, SEM showed reduced porosity and increased grain uniformity. Tauc analysis and UV–Vis spectroscopy revealed a consistent decrease of the bandgap from 2.77 eV to 2.46 eV, which was ascribed to defect-induced electronic states and lattice distortion. The presence of levels of recombination-active defects was further confirmed by photoluminescence spectra. At high temperatures (∼560 °C), dielectric studies revealed a low loss (tanδ = 2.0) and a high dielectric constant (εᵣ ≈800), which made these materials attractive options for wireless communication components. Mg-doped Sr₂FeNbO₆ ceramics have the potential for advanced applications in microwave electronics and optoelectronics due to their superior dielectric behavior, bandgap tunability, and integrated structural stability.