Investigating Li2Mg2(WO4)3: structure, morphology, and electrical properties with ultra-low dielectric loss for optimizing laser host materials

Abstract

With technological advancements driving the demand for innovative materials, triple tungstate compounds, like Li₂Mg₂(WO₄)₃ (LMWO), offer exceptional properties for optoelectronic technologies. To investigate these potential outcomes, the LMWO compound was prepared via the solid-state reaction approach. The X-ray diffraction analysis revealed a single-phase material crystallizing in the orthorhombic structure, belonging to the Pnma space group. The crystallite size of the material was determined to be 58.32 nm, which played a significant role in enhancing its electrical performance. Scanning electron microscopy (SEM) revealed prismatic or rod-shaped particles with an average grain size of approximately 2.83 μm. Additionally, EDX confirmed the elemental composition, verifying the presence of Mg, W, and O, and ensuring the material's purity. Nyquist plots indicated non-Debye type relaxation, and further analysis of the relaxation frequency confirmed long-range motion of charge carriers. The temperature dependence of dielectric relaxation followed the Arrhenius law, yielding an activation energy of 0.84 eV. The frequency dependent behavior of M′′ and Z′′ at various temperatures indicated a shift from short-range to long-range mobility of charge carriers. The conductivity of the material increased with both temperature and frequency, demonstrating its semiconducting behavior. The temperature dependence of Jonscher's exponent suggests that conduction follows the non-overlapping small polaron tunneling (NSPT) model. This compound exhibited a high dielectric constant (ε ∼ 10⁵) and low dielectric loss at high frequencies, making it promising for applications in laser host materials and energy storage.