Evidence for linking an oxygen pairing process and superconductivity in YBa2Cu3O7-delta between 86 and 130 K

Ultrasonic studies at 85 kHz about the T-c region of melt-textured YBa2Cu3O 7-delta (Y123) yielded details of strain amplitude dependent (SAD) and time dependent phenomena. This has provided strong evidence for an oxygen pairi ng process associated with a structural change, which was evident for tempe ratures below T-c up to 130 K. This pairing process has been linked, throug h a variety of experiments, to superconductivity and has provided evidence for the pseudogap phenomenon as well as a possible mechanism for channeling the superconducting carriers. The experiments included an enhanced oxygen related ultrasonic breakaway process in the T-c region, lowering the T-c of Y123 ultrasonically at high strain amplitudes, enhancing superconductivity at low ultrasonic strain amplitudes in the T-c transition, oxygen pairing up to 130 K; (C) 2000 Elsevier Science B.V. All rights reserved.