Microstructure and Dielectric Properties of Ta-doped La₂Ti₂O₇ Ceramics

Abstract

The perovskite-like layer-structured lanthanumtitanate (La₂Ti₂O₇) is a good candidate for high-temperature piezoelectric applications because of its high Curie temperature. In this paper, La₂Ta _x Ti_2-x O₇ (x = 0, 0.1, 0.2, 0.3) (short for LTTO) ultrahigh-temperature piezoelectric ceramics were prepared using conventional solid-state processing. The phase structure, surface morphology, and electrical properties of La₂Ta _x Ti_2-x O₇ ceramics were investigated in detail. The results show that all ceramics possess a high relative density and a single phase. The shape of grains of La₂Ta _x Ti_2-x O₇ ceramics is plate-like and Ta can refine the grains of ceramics. The grains size, dielectric and ferroelectric properties vary with the value of x. The grain size (D ≤ 2 μm) are obtained when x = 0.2. However, the optimum dielectric properties (ϵ_r ≥ 5600, tanδ ≤ 0.02) are obtained when x = 0.3.

Keywords:

• lanthanum titanate
• microstructure
• dielectric properties
• Ta doped

Acknowledgment

This project is supported by Natural Science Foundation Project of CQ CSCT2012 jjA50017, the Research Foundation of Education Bureau of Chongqing, China (No.KJ121408).