High‐permittivity and conduction mechanism of La‐doped Ba0.67Sr0.33TiO3 ceramics

Abstract

AbstractHigh permittivity La‐doped Ba0.67Sr0.33TiO3 ceramics (BSTL) with cubic perovskite structure, i.e., BaxSr1−xTiO3 (BST) + x at.% La, where x = 0–1, were prepared by conventional ceramic processing techniques. Dielectric characteristics, X‐ray diffraction, scanning electron microscopy (SEM), and J–V (leakage current density–voltage) behaviors were measured. Doping with the La in the BST host lattice resulted in a large‐grained (1–3 µm) and fine‐grained (0.3–1 µm) microstructure, marked raising, and broadening of the Curie peak. The temperature of dielectric peak (Tm) at 10 kHz decreased rapidly with a doping concentration of <0.7 at.% La. By means of doping with La, high dielectric constant ceramics (BSTL: 0.2 ≤ x ≤ 0.7) with permittivity at room temperature (εRT) > 110 000 at 10 kHz have been achieved. The plots of leakage current density versus voltage show the different electrical conduction mechanism in different voltage ranges.