  We report the observation of an exceptionally large room-temperature
electrical conductivity in silver and aluminum layers deposited on a lead
zirconate titanate (PZT) substrate. The surface resistance of the silver-coated
samples also shows a sharp change near 313 K. The results are strongly
suggestive of a superconductive interfacial layer, and have been interpreted in
the framework of Bose-Einstein condensation of bipolarons as the suggested
mechanism for high-temperature superconductivity in cuprates.
