Studies on the Dielectric, Structural, and Electronic Properties of Barium-doped Gd₂NiMnO₆ Double Perovskite

This paper explores the structural, dielectric, and electronic properties of Gd₂₋ₓBaₓNiMnO₆ (x=0.0, 0.25, 0.50) double perovskite in great detail. The solid-state reaction technique was utilized in the synthesis process to create Gd₂₋ₓBaₓNiMnO₆ samples. After an extensive examination of the structural and surface morphological characteristics using scanning electron microscopy (SEM) and X-ray diffraction (XRD), a pure phase with a P2₁/n monoclinic space group was identified. Ba doping led to lattice distortion, as evidenced by a shift in diffraction peaks and a decrease in crystallite size. The novelty of this study lies in the systematic investigation of how Ba substitution influences dielectric behavior, crystallite size reduction, and charge carrier dynamics, which are largely unexplored in this context. The dielectric measurements revealed a significant increase in the dielectric constant from 56 (undoped) to 148 (x=0.50), while dielectric loss remained below 0.1 at 1 kHz. Conductivity studies showed a reduction in AC conductivity from 3.2 × 10⁻⁵ S/m (x=0.0) to 1.1 × 10⁻⁵ S/m (x=0.50), indicating improved insulating behavior. To summarize, the synthesized material demonstrates both functional properties and a high dielectric constant, together with reduced dielectric losses and conductivity. Consequently, it becomes a feasible choice for applications involving high-k dielectric materials.