Tunneling measurements on the high-Tc superconductors La1.85Sr0.15CuO4−δ and YBa2Cu3O7−δ
P. J. M. van Bentum, L. E. C. van de Leemput, L. W. M. Schreurs, P. A. A. Teunissen, H. van Kempen
DOI 10.1103/PhysRevB.36.843 · Physical Review B
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Abstract
We have measured the superconducting properties of the new high-Tc superconductors La1.85Sr0.15CuO4−δ and YBa2Cu3O7−δ by electron tunneling. The measured I-V curves can be described neatly with simple tunneling theory, using the Bardeen-Cooper-Schreiffer density of states for the superconductor. For the La-Sr compound we find an energy gap ranging between 10 and 20 meV. By exerting a large pressure on the sample the gap value could be increased to 35 meV. From these measurements we extract 2Δ/kBTc=3.5–4. For the Y-Ba compound we find a pressure-independent gap 2Δ=23±2 meV or 2Δ/kBTc=3.2±0.4.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| La1.85Sr0.15CuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 33 | Pressure unresolved | midpoint |
| La1.85Sr0.15CuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 38 | Pressure unresolved | onset |
| La1.85Sr0.15CuO4-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure unresolved | unknown |
| YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 84 | Pressure unresolved | midpoint |
| YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 91.2 | Pressure unresolved | midpoint |
| YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure unresolved | unknown |
| La1.84Sr0.16CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | — | Pressure not reported | unknown |
| Y1.2Ba0.8CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 90 | Pressure unresolved | onset |
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