Wedgelike ultrathin epitaxial BaTiO3 films for studies of scaling effects in ferroelectrics

A. Petraru, H. Kohlstedt, U. Poppe, R. Waser, A. Solbach, U. Klemradt, J. Schubert, W. Zander, N. A. Pertsev
2008 Applied Physics Letters  
To study ferroelectric size effects in heteroepitaxial SrRuO 3 / BaTiO 3 / SrRuO 3 capacitors, ultrathin BaTiO 3 layers were deposited in wedge form across SrTiO 3 substrates. The wedgelike films were fabricated by using either an off-center substrate-target geometry or via a moveable shutter during high-pressure sputter deposition. The crystallinity, composition, and surface roughness along wedgelike BaTiO 3 films were verified by x-ray diffraction, Rutherford backscattering spectrometry, and
more » ... spectrometry, and atomic force microscopy, respectively. The electrical measurements performed at 77 K showed that, despite progressive reduction in remanent polarization as the film thickness decreases even the 3.5-nm-thick BaTiO 3 film retains a large remanent polarization of 28 C / cm 2 .
doi:10.1063/1.2972135 fatcat:26yyllvu7vgvxiomrbeio4xzqq