Direct structural determination in ultrathin ferroelectric films by analysis of synchrotron x-ray scattering measurements
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)
- Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)
- Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States)
- FOCUS Center, Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)
- National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)
- Physics Department, University of Washington, Seattle, Washington 98195-1560 (United States)
In order to better understand ferroelectricity in thin films, it is important to explore the atomic-scale structure and the spatial distribution of polarization near the interfaces. We present sub-Angstrom-resolution electron density maps of three ultrathin PbTiO{sub 3} films grown epitaxially on SrTiO{sub 3} (001) substrates. The maps were obtained by analysis of synchrotron x-ray scattering measurements of Bragg rod intensities using the recently developed coherent Bragg rod analysis method. A four- and a nine-unit-cell-thick film were studied at room temperature, and a nine-unit-cell-thick film was studied at 181 deg. C. The results show that at room temperature, the PbTiO{sub 3} films are polar, monodomain, and have their polarization oriented away from the substrate. The four-unit-cell film may be the thinnest monodomain perovskite film found to be in the polar phase. At 181 deg. C, the electron density map of the nine-unit-cell film is consistent with the presence of 180 deg. stripe domains. In the monodomain samples, details of the atomic-scale structure of the PbTiO{sub 3}/SrTiO{sub 3} interface are observed, which may provide evidence for the nature of the positive charge layer required to stabilize polarization in monodomain films.
- OSTI ID:
- 20666314
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 71, Issue 14; Other Information: DOI: 10.1103/PhysRevB.71.144112; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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