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Research Highlight

Dynamic Tuning of Local Defect Concentration Delivers Enhanced Electromechanical Response

Dynamic tuning of local defect concentration delivers enhanced electrochemical response.
Piezoresponse force microscopy spectrogram (top) shows an increase in contact resonance frequency and amplitude per cycle. Off-field amplitude vs. bias for 3 cycles (bottom left) illustrating an enhanced electromechanical response with increasing cycles. Analytical model of strain-voltage loops (bottom right) with increasing oxygen vacancy concentration.

Scientific Achievement

A new mechanism was discovered enabling the electromechanical response in BaTiO3 (BTO) to be enhanced by a factor of 4.8.

Significance and Impact

This mechanism of bias induced oxygen vacancy injection via scanning probe microscopy (SPM) enabled the superior electromechanical response, providing an alternative route toward improving ferroelectrics for actuators and sensing.

Research Details

  • Piezoresponse force microscopy performed at elevated temperatures was used to explore the dynamics of oxygen vacancies in BTO.

  • Density functional theory, reactive force field, and thermodynamic modeling all support a mechanism of vacancy-assisted enhancement of the electromechanical response

     

K.P. Kelley, et al., Advanced Materials, 2106426 (2021). https://doi.org/10.1002/adma.202106426

Work was performed at the Center for Nanophase Materials Sciences and the National Institute for Computational Sciences at Oak Ridge National Laboratory, the Pennsylvania State University, National Academy of Science Ukraine, and the University of Tennessee