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Studies of Local Structural Distortions in Strained Ultrathin BaTiO3 Films Using Scanning Transmission Electron Microscopy

  • Daesung Park (a1) (a2), Anja Herpers (a3), Tobias Menke (a3), Markus Heidelmann (a4) (a2), Lothar Houben (a4) (a2), Regina Dittmann (a3) and Joachim Mayer (a1) (a2)...

Abstract

Ultrathin ferroelectric heterostructures (SrTiO3/BaTiO3/BaRuO3/SrRuO3) were studied by scanning transmission electron microscopy (STEM) in terms of structural distortions and atomic displacements. The TiO2-termination at the top interface of the BaTiO3 layer was changed into a BaO-termination by adding an additional BaRuO3 layer. High-angle annular dark-field (HAADF) imaging by aberration-corrected STEM revealed that an artificially introduced BaO-termination can be achieved by this interface engineering. By using fast sequential imaging and frame-by-frame drift correction, the effect of the specimen drift was significantly reduced and the signal-to-noise ratio of the HAADF images was improved. Thus, a quantitative analysis of the HAADF images was feasible, and an in-plane and out-of-plane lattice spacing of the BaTiO3 layer of 3.90 and 4.22 Å were determined. A 25 pm shift of the Ti columns from the center of the unit cell of BaTiO3 along the c-axis was observed. By spatially resolved electron energy-loss spectroscopy studies, a reduction of the crystal field splitting (CFS, ΔL3=1.93 eV) and an asymmetric broadening of the e g peak were observed in the BaTiO3 film. These results verify the presence of a ferroelectric polarization in the ultrathin BaTiO3 film.

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Corresponding author

* Corresponding author. park@gfe.rwth-aachen.de

References

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Ávila-Brande, D., Boese, M., Houben, L., Schubert, J. & Luysberg, M. (2011). Strain-induce shift of the crystal-field splitting of SrTiO3 embedded in scandate multilayers. ACS Appl Mater Interfaces 3, 15451551.
Bals, S., Tirry, W., Geurts, R., Yang, Z. & Schryvers, D. (2007). High-quality sample preparation by low kV FIB thinning for analytical TEM measurements. Microsc Microanal 13, 8086.
Brydson, R., Sauer, H., Engel, W., Thomass, J., Zeitler, E., Kosugi, N. & Kuroda, H. (1989). Electron energy loss and X-ray absorption spectroscopy of rutile and anatase: A test of structural sensitivity. J Phys Condens Matter 1, 797812.
Duan, C., Sabirianov, R., Mei, W., Jaswal, S. & Tsymbal, E. (2006). Interface effect on ferroelectricity at the nanoscale. Nano Lett 6, 483487.
Eberg, E., Van Helvoort, A.T.J., Takahashi, R., Gass, M., Mendis, B., Bleloch, A., Holmestad, R. & Tybell, T. (2011). Electron energy loss spectroscopy investigation of Pb and Ti hybridization with O at the PbTiO3/SrTiO3 interface. J Appl Phys 109, 034104.
Goodhew, P. (2011). General introduction to transmission electron microscopy (TEM). In Aberration-Corrected Analytical Electron Microscopy, Brydson R. (Ed.), pp. 119. Hoboken, NJ, USA: Wiley & Sons.
Harada, J., Pedersen, T. & Barnea, Z. (1970). X-ray and neutron diffraction study of tetragonal barium titanate. Acta Crystallogr Sect A 26, 336344.
Heidelmann, M., Barthel, J. & Houben, L. (2009). StripeSTEM, a technique for the isochronous acquisition of high angle annular dark-field images and monolayer resolved electron energy loss spectra. Ultramicroscopy 109, 14471452.
Houben, L. (2009). iMtools software package for digital image processing of electron micrographs, Research Center Jülich. Available at http://www.er-c.org/methods/software.htm. Accessed October 28, 2013.
Houben, L., Thust, A. & Urban, K. (2006). Atomic-precision determination of the reconstruction of a 90° tilt boundary in YBa2Cu3O7-δ by aberration corrected HRTEM. Ultramicroscopy 106, 200214.
Jan, J., Kumar, K., Chiou, J., Tsai, H., Shih, H., Hsueh, H., Ray, S., Asokan, K., Pong, W., Tsai, M.-H., Kuo, S. & Hsieh, W. (2003). Effect of the Ca content on the electronic structure of Pb1-xCaxTiO3 perovskites. Appl Phys Lett 83, 33113313.
Jia, C., Nagarajan, V., He, J., Houben, L., Zhao, T., Ramesh, R., Urban, K. & Waser, R. (2006). Unit-cell scale mapping of ferroelectricity and tetragonality in epitaxial ultrathin ferroelectric films. Nature Mater 6, 6469.
Junquera, J. & Ghosez, P. (2003). Critical thickness for ferroelectricity in perovskite ultrathin films. Nature 422, 506509.
Lu, H., Liu, X., Burton, J.D., Bark, C.-W., Wang, Y., Zhang, Y., Kim, D.J., Stamm, A., Lukashev, P., Felker, D.A., Folkman, C.M., Gao, P., Rzchowski, M.S., Pan, X.Q., Eom, C.-B., Tsymbal, E.Y. & Gruverman, A. (2012). Enhancement of ferroelectric polarization stability by interface engineering. Adv Mater 24, 12091216.
Mayer, J., Giannuzzi, L.A., Kamino, T. & Michael, J. (2007). TEM sample preparation and FIB-induced damage. MRS Bulletin 32, 400407.
Petraru, A., Pertsev, N., Kohlstedt, H., Poppe, U., Waser, R., Solbach, A. & Klemradt, U. (2007). Polarization and lattice strains in epitaxial BaTiO3 films grown by high-pressure sputtering. J Appl Phys 101, 114106.
Sefat, A.S., Amow, G., Wu, M.-Y., Botton, G.A. & Greedan, J. (2005). High-resolution EELS study of the vacancy-doped metal/insulator system, Nd1-xTiO3, x= 0 to 0.33. J Solid State Chem 178, 10081016.
Stengel, M., Vanderbilt, D. & Spaldin, N. (2009). Enhancement of ferroelectricity at metal-oxide interfaces. Nat Mater 101, 392397.
Torres-Pardo, A., Gloter, A., Zubko, P., Jecklin, N., Lichtensteiger, C., Colliex, C., Triscone, J.-M. & Stéphan, O. (2011). Spectroscopic mapping of local structural distortions in ferroelectric PbTiO3/SrTiO3 superlattices at the unit-cell scale. Phys Rev B 84, 220102.
Umeno, Y., Shimada, T., Kitamura, T. & Elsässer, C. (2006). Ab initio density functional theory study of strain effects on ferroelectricity at PbTiO3 surfaces. Phys Rev B 74, 174111.
Zhang, J., Visinoiu, A., Heyroth, F., Syrowatka, F., Alexe, M., Hesse, D. & Leipner, H.S. (2005). High-resolution electron energy-loss spectroscopy of BaTiO3/SrTiO3 multilayers. Phys Rev B 71, 064108.

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