Scandium and gadolinium co-doped BaTiO3 nanoparticles and ceramics prepared by sol–gel–hydrothermal method: Facile synthesis, structural characterization and enhancement of electrical properties

Abstract

A facile sol–gel–hydrothermal process was used to synthesize Scandium and Gadolinium co-doped BaTiO3 nanocrystals in this paper. Similar to the previous studies, a single-phase solid-solution structure is hard to achieve for BaTiO3 materials doped with rare-earth ions like Sc- and Gd- via solid-state method. Here, uniform Ba1−xTi1−xGdxScxO3 (0≤x≤0.04) nanoparticles (NPs) with single-phase solid-solution cubic structure and average particle size of 30–40nm were obtained and Ba1−xTi1−xGdxScxO3 pellets prepared from as-synthesized nanopowders can be sintered at a lower temperature of 1150°C. The internal structures, chemical constitution and morphology were characterized by FT-IR spectra, XRD, TEM, HRTEM, Raman spectra and SEM analysis. The results clearly demonstrated that Sc3+ and Gd3+ have entered into the BaTiO3 lattice and led to structural distortion in a short range and all samples were single-phase tetragonal structure at room temperature. Additionally, the dielectric temperature stability was enhanced with Sc3+ and Gd3+ as dopants, since the single-phase BaTiO3 ceramics exhibited broadened dielectric peaks, decline of Curie temperature as well as low dielectric loss below 0.02. Ceramics containing 3mol% Sc3+ and Gd3+ can exhibit the best dielectric behaviour of εr ~1700 and Tc=32°C in this work.