Abstract
To understand the influence of epitaxial strain, depolarizing field, and intrinsic surface effects on the ferroelectric transition, we have investigated ferroelectric thin films using synchrotron x-ray scattering. Here we summarize real-time studies of epitaxial PbTiO3 film growth on SrTiO3 by metalorganic chemical vapor deposition (MOCVD), and in situ studies of the ferroelectric transition as a function of temperature and film thickness. The ability to monitor growth in real time using x-ray scattering allows us to produce films with smooth interfaces, well-defined strain states, and thicknesses controlled to sub-unit-cell accuracy. We find that the ferroelectric phase forms as 180° stripe domains in these films, with a thickness-dependent Tc. The dependence of the stripe period on film thickness is in agreement with theory. For thicker films (e.g. 40 nm), we find that Tc is elevated above the unstressed bulk value by an amount that agrees with theory for the effect of epitaxial strain. However, the observed decrease of Tc for smaller film thickness is significantly larger than that expected solely due to 180° stripe domains, indicating that intrinsic surface or interface effects may also be important.
Original language | English |
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Title of host publication | Polar Oxides |
Subtitle of host publication | Properties, Characterization, and Imaging |
Publisher | Wiley-VCH Verlag GmbH & Co. KGaA |
Pages | 151-161 |
Number of pages | 11 |
ISBN (Print) | 3527405321, 9783527405329 |
DOIs | |
State | Published - Aug 9 2005 |
Keywords
- Growth of ultrathin ferroelectric films
- In-situ synchrotron X-ray studies of processing and physics of ferroelectric thin films