Study on the anomalies of YBa2Cu3O9-xbetween 90 and 260 K by elasticity measurements and X-ray diffraction

Abstract

The internal friction (Q^-1), ultrasonic attenuation ( alpha ) and variation of Young's modulus ( Delta E/E) of YBa₂Cu₃O_9-x were measured with frequencies of 5 kHz, 120 kHz and 5 MHz. Several Q^-1 (or alpha ) peaks and corresponding minima of Delta E/E were observed. According to X-ray diffraction results, the Q^-1 peak as well as other anomalies can be attributed to a discontinuous change of lattice parameters. The tendency to elastic softening above 90 K may play an important role in superconductivity.