Effect of La3+ content on the properties of ferroelectric Bi4-xLaxTi3O12 (BLT) thin films prepared by aqueous chemical solution deposition

作者：Hardy A^*; Van Bael M K; Van den Rul H; Vangenechten D; Mullens J; D'Haen J; Goux L; Wouters D J

来源：Journal of Sol-Gel Science and Technology, 2007, 42(3): 239-245.

DOI：10.1007/s10971-007-0742-2

• aqueous solution-gel precursor
• chemical solution deposition
• ferroelectric
• BLT
• XRD
• SEM
• X-TEM

Lanthanum substituted bismuth titanate thin films were deposited using an aqueous chemical solution deposition method. Varying the composition of Bi4-xLaxTi3O12, with x = 0.5, 0.65, 0.75 and 0.85, is shown to have a large influence on the microstructure and properties of the films. Increasing the amount of La3+, x, from 0.5 to 0.85 led to a decrease of the remanent polarization (P-r) from 6.2 to eventually 0 mu C/cm(2). This decrease of P-r is explained by means of X-ray diffraction (XRD) study, which shows that there is an increased preference for c-axis orientation upon increasing the La3+ concentration. Furthermore, a strong decrease of the grain size upon increasing x is observed in a scanning electron microscopic (SEM) study. The concurrent increase of domain pinning on the grain boundaries is a second effect which may be responsible for the deterioration of the ferroelectric property at larger x.

• 出版日期2007-6