Pyroelectric and Piezoelectric Effects in Single Crystals of YBa2Cu3O(7-Delta)

摘要

The possibility of ferroelectric (or antiferroelectric) behavior in high-Tcmaterials is suggested by the well known tendency of the perovskite structure to distort and form such ordered phases. Moreover, the connection between incipient (anti)ferroelectricity and superconductivity has been made by a number of authors. However, the crystal structure of YBa2Cu3O7 as determined by X-ray and neutron diffraction measurements has been reported to be centrosymmetric and, therefore, not ferroelectric. In this paper, we report the observation of a transient voltage across the z-axis of a single crystal upon heating with thermal or laser pulses as well as a transient voltage across the z-axis resulting from the application of mechanical stress.