Journal of Materials Research

Articles

Compositional tuning of the strain-induced structural phase transition and of ferromagnetism in Bi1−xBaxFeO3−δ

Charlee J.C. Bennetta1, Hyun Sik Kima2, Maria Varelaa3, Michael D. Biegalskia4, Dae Ho Kima5, David P. Nortona6, Harry M. Meyer IIIa7 and Hans M. Christena8 c1

a1 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

a2 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; and Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom

a3 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

a4 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

a5 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; and Department of Physics, Tulane University, New Orleans, Louisiana 70118

a6 Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611

a7 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

a8 Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831; and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

Abstract

Recent studies by a number of research groups have shown that the structure of epitaxial BiFeO3 (BFO) films changes drastically as a function of substrate-induced biaxial compression, with the crystal structure changing from one being nearly rhombohedral (R-like) to one being nearly tetragonal (T-like), where the “T-like” structure is characterized by a highly enhanced c/a ratio of out-of-plane c to in-plane a lattice parameters. In this work, we show that the critical compressive strain σc necessary to induce this transition can be reduced significantly by substituting 10% Ba for Bi [Bi0.9Ba0.1FeO3−δ (BBFO)] and that the “T-like” phase in both BBFO and BFO is stable up to the decomposition temperatures of the films in air. Furthermore, our results show that the BBFO solid solution shows clear ferromagnetic properties in contrast to its undoped BFO counterpart.

(Received November 09 2010)

(Accepted February 18 2011)

(Online publication May 13 2011)

Key Words:

  • Ferroelectric;
  • Ferromagnetic;
  • Epitaxy

Correspondence:

c1 Address all correspondence to this author. e-mail: christenhm@ornl.gov

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