Impact of symmetry on the ferroelectric properties of CaTiO{sub 3} thin films
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16801 (United States)
- Stanford Synchrotron Lightsource SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California 95616 (United States)
Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO{sub 3}, through the careful control of the biaxial strain state and TiO{sub 6} octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO{sub 3} films grown on La{sub 0.18}Sr{sub 0.82}Al{sub 0.59}Ta{sub 0.41}O{sub 3} (LSAT) and NdGaO{sub 3} (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO{sub 6} octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization ∼5 μC/cm{sup 2} at 10 K and T{sub c} near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and T{sub c}. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films.
- OSTI ID:
- 22398932
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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