EFFECT OF BISMUTH EXCESS ON THE CRYSTALLIZATION OF Bi3.25La0.75Ti3O12 CERAMIC AND THIN FILM

Abstract

ABSTRACT Varying amount of Bi2O3 excess Bi3.25La0.75Ti3O12 (BLT) ceramics were prepared by solid state reaction and BLT thin films were fabricated on Pt/TiO2/SiO2/Si using RF magnetron sputtering method. The effect of Bi2O3 excess content on the microstructure and ferroelectric properties of the BLT ceramic and thin film was investigated. The X-ray diffraction analysis reveals a layered peroviskite structure phase without pyrochlore phase in all the BLT ceramics with varying amounts of Bi2O3 excess. The SEM micrographs of the BLT ceramics show plate-like morphology. Compared with other BLT thin films with different amount of Bi2O3 excess, the BLT thin film with 10% Bi2O3 excess shows higher degree of squareness and larger remnant value (2Pr). The remnant polarization (2Pr) and coercive voltage (Vc) of the BLT thin film with 10% Bi2O3 excess are about 17.6 μ C/cm2 and 3.7 V, respectively. The BLT thin film with 10% Bi2O3 excess shows the best fatigue resistance characteristics among all the BLT films and just about 9% polarization degradation was observed in the film after 1× 109 read/write switching cycles.