Abstract
For epitaxial films, a critical thickness (t c) can create a phenomenological interface between a strained bottom layer and a relaxed top layer. Here, we present an experimental report of how the t c in BiFeO 3 thin films acts as a boundary to determine the crystalline phase, ferroelectricity, and piezoelectricity in 60 nm thick BiFeO 3 /SrRuO 3 /SrTiO 3 substrate. We found larger Fe cation displacement of the relaxed layer than that of strained layer. In the time-resolved X-ray microdiffraction analyses, the piezoelectric response of the BiFeO 3 film was resolved into a strained layer with an extremely low piezoelectric coefficient of 2.4 pm/V and a relaxed layer with a piezoelectric coefficient of 32 pm/V. The difference in the Fe displacements between the strained and relaxed layers is in good agreement with the differences in the piezoelectric coefficient due to the electromechanical coupling.
Original language | English |
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Article number | 38724 |
Journal | Scientific Reports |
Volume | 6 |
DOIs | |
State | Published - Dec 8 2016 |