Evidence for two hysteresis loops in YBa2Cu3O6 +x ultrasonic velocity measurements

Biagi, E.; Masotti, L.; Borchi, E.; Masi, L.; Garrè, R.; Gennaro, S. De

doi:10.1002/pssa.2211380123

Cited by 6 publications

(1 citation statement)

References 14 publications

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“…The effect of porosity on the hysteresis is also minimal because similar hysteresis in the temperature dependence of Young's modulus by the vibrating reed technique [18,32] and also in the temperature dependence of C 33 and C 44 ultrasonic modes [33] [35]. An inspection of the phase diagram suggested a first-order phase transition corresponding to crossing over the boundary between the Ortho-I and mixed Ortho-I and Ortho-III phases in the temperature range of 200 K-230 K [5,36]. A similar oxygen ordering mechanism may also cause the 190 K-230 K hysteresis in ErBa 2 Cu 3 O 7−δ since Ortho-I and Ortho-II related plateaus indicating the existence of different orthorhombic superstructures were observed in its T c versus oxygen content graphs [17,18].…”

Section: Resultsmentioning

confidence: 99%

The effects of oxygen content and Pr substitution on ultrasonic velocity in superconductors

Yahya

Abd‐Shukor

1998

Supercond. Sci. Technol.

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Ultrasonic velocity measurements on superconducting (x = 0, 0.1 and 0.2) with and non-superconducting were performed at 10 MHz using the pulsed echo overlap ultrasonic system. Pr substitution in the samples caused a systematic increase in the absolute shear and longitudinal velocities. The reduction of oxygen content to , however, caused a decrease in both absolute velocities. The and samples showed a similar per cent change in velocity of about 3.8% (longitudinal) between 80 K and 300 K and 2.3% (shear) between 80 K and 220 K. In addition, a longitudinal velocity hysteresis was observed in both samples between 190 K and 220 K. A smaller per cent change in velocities was observed for the superconducting and non-superconducting samples. The effects of Pr substitution and oxygen depletion on the change of velocity and the 190 K-230 K longitudinal velocity hysteresis were explained in terms of possible oxygen ordering in the materials.

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