Electrical Properties of La_2−xCe_xTi₂O₇ (x = 0–0.1) Ceramics

Abstract

As an important functional material, the applications of piezoelectric materials have shifted from convenient use to service in extreme environments. Herein, a new layered high‐temperature ceramic La2Ti2O7 (LTO) with the substitution of La3+ ions by Ce3+ ions at A sites is designed and synthesized using the conventional solid‐state sintering technology. The effects of dopant Ce3+ ions on the microstructure, phase structure, and electrical properties of LTO are investigated methodically. Moderate dopant Ce3+ ions decrease the concentration of thermions in LTO ceramics, but excess dopant Ce3+ ions can lead to cell distortions, which have some relationships with defects. Through analysis, the La1.95Ce0.05Ti2O7 (LCTO‐0.05) ceramics with a pure monoclinic phase possess optimal electrical properties. At 650 °C, the enhanced fitted direct current (DC) resistivity of the LCTO‐0.05 ceramics is 1.5 × 106 Ω cm. The activation energy of conductivity and relaxation activation energy of imaginary impedance Z″ for LCTO‐0.05 ceramics are 1.12 and 1.16 eV, respectively, in the high‐temperature regime. The piezoelectric coefficient d33 of LCTO‐0.05 ceramics is up to 3.6 pCN−1. It is believed that this ceramic system promotes the development of LTO‐based high‐temperature piezoelectric ceramics.