Effect of substitution of vanadium on the structure and electrical properties of Bi3.25La0.75Ti3O12 thin films
The ferroelectric and dielectric properties of Bi4-xLaxTi3O12 (BLT) and Bi4-xLaxTi2.97V0.03O12 (BLTV) thin films deposited on (111)Pt/Ti/SiO2/Si substrates using a chemical solution method were investigated. The BLTV thin films showed a larger remanent polarization (9.6 μC/cm2) than the BLT thin films (6.5 μC/cm2), while the coercive field for both thin films was nearly the same. The capacitance of the films as a function of a small ac driving field was measured, and the data were processed using Rayleigh's law. The results show that the Rayleigh constant of the BLT films was smaller than that of the BLTV films, indicating that the defect concentration was lower in the latter case. The superior ferroelectricity of the BLTV films was attributed to a decrease of both the (001) orientation and the defect concentration.