The experimental measurement of second harmonic generation (SHG) and theoretical correlation of the SHG output to domain microstructure is presented for ferroelectric KNbO3 (110) thin films on a SrTiO3 (100) substrate. From X-ray diffraction, four possible domain variants in the film growth plane were determined to be KNbO3 ∥SrTiO3 , , , or  denoted as variants X+, X-, Y+, and Y-, respectively. From theoretical modeling of the SHG output from the film, the ratios of nonlinear coefficients d0/d32 and d24/d0 in the film were determined to be 2.19 ± 0.12 and 0.46 ± 0.26, respectively, in good agreement with the bulk KNbO3 crystals. The term d0 is defined as d15 + (d31 + d33)/2. The SHG can also distinguish between X+ and X-, as well as Y+ and Y-, domains, which was not possible by X-ray diffraction. The ratio of net area fraction (|AX+ - AX-|/|AY+ - AY-|) was determined to be 2.76 ± 1.06 in the probe area (2.25π mm2) where AX+, AX-, AY+, and AY- are the area fractions of domain variants X+, X-, Y+, and Y-, respectively, in the film growth plane.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of the American Ceramic Society|
|State||Published - Dec 1996|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry