Large electromechanical strain and unconventional domain switching near phase convergence in a Pb-free ferroelectric

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  • Sarangi Venkateshwarlu, City University of Hong Kong
  • ,
  • Lalitha K. Venkataraman, Technische Universität Darmstadt
  • ,
  • Valentin Segouin, Universite Paris-Saclay, Sorbonne Université
  • ,
  • Frederick P. Marlton
  • ,
  • Ho Chin Hin, City University of Hong Kong
  • ,
  • Dmitry Chernyshov, St. Petersburg State Polytechnical University, SNBL, ESRF
  • ,
  • Yang Ren, Argonne National Laboratory
  • ,
  • Mads R.V. Jørgensen
  • Sanjib Nayak, City University of Hong Kong
  • ,
  • Jürgen Rödel, Technische Universität Darmstadt
  • ,
  • Laurent Daniel, Universite Paris-Saclay, Sorbonne Université
  • ,
  • Abhijit Pramanick, City University of Hong Kong

In many ferroelectrics, large electromechanical strains are observed near regions of composition- or temperature- driven phase coexistence. Phenomenologically, this is attributed to easy re-orientation of the polarization vector and/or phase transition, although their effects are highly convoluted and difficult to distinguish experimentally. Here, we used synchrotron X-ray scattering and digital image correlation to differentiate between the microscopic mechanisms leading to large electrostrains in an exemplary Pb-free piezoceramic Sn-doped barium calcium zirconate titanate. Large electrostrains of ~0.2% measured at room-temperature are attributed to an unconventional effect, wherein polarization switching is aided by a reversible phase transition near the tetragonal-orthorhombic phase boundary. Additionally, electrostrains of ~0.1% or more could be maintained from room temperature to 140 °C due to a succession of different microscopic mechanisms. In situ X-ray diffraction elucidates that while 90° domain reorientation is pertinent below the Curie temperature (TC), isotropic distortion of polar clusters is the dominant mechanism above TC.

Original languageEnglish
Article number193
JournalCommunications Physics
Number of pages14
Publication statusPublished - Oct 2020

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