Acoustoelectric effects in ceramic high-temperature superconductors using a separate medium structure

The interaction of the surface acoustic wave (SAW) with a bulk ceramic high-temperature superconductor is investigated using a contactless separate medium structure. The superconductor is part of a sandwich structure consisting of a y-cut z-propagating LiNbO3 SAW delay line. An acoustoelectric voltage is observed across the superconductor above the transition temperature. The magnitude of this voltage exhibits large changes as a function of temperature. As the temperature decreases through the superconductive transition, the acoustoelectric voltage vanishes abruptly. The transition temperature for the acoustoelectric voltage is in agreement with resistivity measurements performed on the same sample.