Study on Ferroelectric and Dielectric Properties of La-Doped CaBi_4Ti_4O_(15)-Based Ceramics

摘要

Lanthanum doped bismuth layer structured ferroelectrics (BLSFs) Ca1-xLaxBi4(Ti0.9W0.1)4O15 (x=0, 0.2, 0.3, 0.4, 0.6) ceramics were prepared by solid-state reaction method. X-ray diffraction(XRD) patterns showed that single phase was formed when x=0～0.6. The effects of La3+ doping on dielectric, piezoelectric and ferroelectric properties of Ca1-xLaxBi4(Ti0.9W0.1)4O15 ceramics were studied. Ca0.7La0.3Bi4(Ti0.9W0.1)4O15 ceramic had optimal properties, its dielectric constant was 166.85, dielectric loss was 0.0063, piezoelectric strain constant was 11 pc·N-1, remanent polarization was 18.1 μC·cm-2 and coercive field was 118 kV·cm-1. SEM micrographs showed that the grains of CaBi4Ti4O15-based ceramics were plate-like. The results of energy spectrum analysis (EDS) showed that La3+ incorporation could increase Bi/Ca ratio.