Effect of La2O3 Doping on Phase Formation, Microstructure and Electrical Properties of (K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3 Ceramics Synthesized via the Solid-State Combustion Method

Abstract

In this work, the effect of La2O3 doping (x = 0–1.6 wt%) on the phase formation, microstructure and electrical properties of (K0.44Na0.52Li0.04)(Nb0.84Ta0.10Sb0.06)O3 (KNLNTS) ceramics was investigated. These samples were fabricated by the solid-state combustion method using glycine as fuel. The KNLNTS ceramics doping with La2O3 powders were calcined and sintered at 750 °C and between 1100 and 1200 °C, respectively, for 2 h. From the X-ray diffraction (XRD) results, the ceramics had a pure perovskite phase with coexisting orthorhombic and tetragonal phases in all samples. The Rietveld refinement analysis suggested that the tetragonality increased with increasing La2O3 doping. The grain morphology of the ceramics exhibited a rather square shape. The average grain size and the density of the ceramics tended to decrease from 1.5 to 0.7 µm and 4.71 to 4.56 g/cm3, respectively, when increasing La2O3 contents from 0 to 1.6 wt%. The dielectric behavior of the ceramics degenerated with La2O3 doping. A decrease in the leakage current and saturated hysteresis loops were observed in the samples doped with La2O3 ≥ 0.8 wt%. © 2021 Taylor & Francis Group, LLC.