Ferroelectric Size-effect on BiFeO$_{3}$ Films in Ultra-high Vacuum

ORAL

Abstract

The ferroelectric size effect is a highly pursued and controversial topic encompassing the scaling of polar distortion, domain structure and switchable polarization. We have studied epitaxial BiFeO$_{3}$ films using ultrahigh vacuum piezoresponse force microscopy. The films in vacuum develop out-of-plane polarization domains which, based on their lateral dimensions, drastically violate the Kittel law. From the analysis of the piezoresponse amplitude, we have established that the presence of a topographic island induces in-plane rotation of the polarization vector by 90$^{o}$. These findings are analyzed using a first-principles based model Hamiltonian approach. We have also obtained stable and reproducible piezoresponse hysteresis loops on the 2 nm films. Experiments conducted at the Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, sponsored by the Division of Scientific User Facilities, U.S. Department of Energy.

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Authors

  • Peter Maksymovych

    Oak Ridge National Laboratory, TN, 37831

  • Stephen Jesse

    Oak Ridge National Laboratory, TN, 37831

  • Sergey Lisenkov

    University of Arkansas, AK, 72701

  • Laurent Bellaiche

    21-st century Professor in Nanotechnology, University of Arkansas, AK, 72701

  • Nina Balke

    University of California, Berkeley, CA, 94720

  • Mark Huijben

    University of California, Berkeley, CA, 94720

  • R. Ramesh

    University of California at Berkeley, University of California, Berkeley, CA, 94720, University of California-Berkeley, Department of Physics, and Material Science and Engineering, University of California, Berkeley, CA 94720, USA., Department of Physics, UC Berkeley, Dept. of Materials Science and Engineering, University of California, Berkeley, CA 94720

  • Arthur P. Baddorf

    Oak Ridge National Laboratory, TN, 37831

  • Sergei V. Kalinin

    Oak Ridge National Laboratory, TN 37831, Oak Ridge National Laboratory, TN, 37831