Anomalous ultrasound propagation in the high-Tc superconductors: La1.8Sr0.2CuO4−y and YBa2Cu3O7−δ

S. Bhattacharya; M. J. Higgins; D. C. Johnston; A. J. Jacobson; J. P. Stokes; J. T. Lewandowski; D. P. Goshorn

doi:10.1103/PhysRevB.37.5901

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Anomalous ultrasound propagation in the high-Tc superconductors: La1.8Sr0.2CuO4−y and YBa2Cu3O7−δ

S. Bhattacharya, M. J. Higgins, D. C. Johnston, A. J. Jacobson, J. P. Stokes, J. T. Lewandowski, D. P. Goshorn

DOI 10.1103/PhysRevB.37.5901 · Physical Review B

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Abstract

Attenuation and velocity of longitudinal ultrasound in both known classes of the high-Tc copper-oxide superconductors are found to be highly anomalous compared to conventional superconductors. Attenuation shows a pronounced peak below Tc followed by an approximately power-law decrease at low T. The velocity shows a discontinuity in its temperature derivative at Tc followed by a large increase. The results are inconsistent with dominant contributions from the carriers alone. Anomalies are also observed at higher temperatures suggesting the existence of other phase transitions.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La1.8Sr0.2CuO4-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La1.85Sr0.15CuO4-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown