Large piezoelectricity in electric-field modified single crystals of SrTiO3

Defect engineering is an effective and powerful tool to control the existing material properties and produce completely new ones, which are symmetry-forbidden in a defect-free crystal. For example, the application of astatic electric field to asingle crystal of SrTiO3 forms a strained near-surface layer through the migration of oxygenvacancies out of the area beneath the positively chargedelectrode. While it was previously shown that this near-surface phase holds pyroelectric properties, which are symmetry-forbidden in centrosymmetric bulk SrTiO3, this paper reports that the same phase is stronglypiezoelectric. We demonstrate the piezoelectricity of this phase through stroboscopic time-resolvedX-ray diffraction under alternatingelectric field and show that the effectivepiezoelectric coefficient d33 ranges between 60 and 100 pC/N. The possible atomistic origins of thepiezoelectric activity are discussed as a coupling between the electrostrictive effect and spontaneouspolarization of this near-surface phase.

Source: Applied Physics Letters - November 29, 2016 Category: Physics Authors: B. Khanbabaee, E. Mehner, C. Richter, J. Hanzig, M. Zschornak, U. Pietsch, H. St öcker, T. Leisegang, D. C. Meyer and S. Gorfman Source Type: research