Effects of oxygen inhomogeneities on the properties of YBa2Cu3O7-δ crystals

Many of the unusual physical properties exhibited by high-temperature superconductors have been assumed to be intrinsic and thus have been interpreted as being the result of a novel form of superconductivity. Magnetization and electronic transport measurements on YBa2Cu3O7-δ crystals with varying oxygen deficiency, δ (as determined from their c-lattice parameters) show that this material displays granular-like behavior and transport properties that are very sensitive to oxygen defects. These measurements are important because they show that extrinsic factors must be considered in interpreting measurements made on these materials. (orig.)