Nonlinear piezoelectricity in epitaxial ferroelectrics at high electric fields
Alexei Grigoriev1, Rebecca Sichel, Ho Nyung Lee
1Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
Physical Review Letters
|February 1, 2008
Summary
Nonlinear piezoelectric effects were observed in lead zirconate titanate ferroelectric thin films under high electric fields. These findings confirm theoretical predictions of strain coupling anomalies in ferroelectric materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid State Chemistry
Background:
- Ferroelectric materials exhibit coupling between electric polarization and elastic strain.
- Nonlinear effects in this coupling are theoretically predicted under high electric fields.
- Experimental validation is crucial for understanding ferroelectric behavior.
Purpose of the Study:
- To experimentally investigate nonlinear effects in the polarization-strain coupling of ferroelectric thin films.
- To test theoretical predictions at high electric fields and significant strain levels.
Main Methods:
- Utilized a lead zirconate titanate (PbZr0.2Ti0.8O3) ferroelectric thin film.
- Applied electric fields in the range of several hundred MV/m.
- Measured piezoelectric strain up to 2.7%.
Main Results:
- Observed piezoelectric strain exceeding predictions based on constant piezoelectric coefficients.
- This deviation occurred at electric fields between approximately 200 and 400 MV/m.
- Results are consistent with predicted nonlinear effects at high piezoelectric distortions.
Conclusions:
- Experimental evidence supports the existence of nonlinear polarization-strain coupling in ferroelectric thin films.
- The study validates theoretical models for ferroelectric materials under extreme electric fields.
- Findings contribute to the understanding of advanced ferroelectric device performance.
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