Impact of symmetry on the ferroelectric properties of CaTiO3 thin films

M D Biegalski, L Qiao, Y J Gu, A Mehta, Q He, Y Takamura, A Borisevich, L Q Chen

    Research output: Contribution to journalArticlepeer-review

    Abstract

    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, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (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 TiO6 octahedral in films grown on LSAT substrates resulted in a robust ferroelectric I4 mm phase with remnant polarization similar to 5 mu C/cm(2) at 10 K and T-c near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and T-c. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films. (C) 2015 AIP Publishing LLC.
    Original languageEnglish
    Article number162904
    JournalApplied Physics Letters
    Volume106
    Issue number16
    DOIs
    Publication statusPublished - 22 Apr 2015

    Keywords

    • perovskite

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