R2Ba4Cu7O15−δ: A 92-K bulk superconductor
J. L. Tallon, D. M. Pooke, R. G. Buckley, M. R. Presland, F. J. Blunt
DOI 10.1103/PhysRevB.41.7220 · Physical Review B
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
Superconductivity is investigated in R2Ba4Cu7O15−δ (R=Y or Er) as a function of oxygen stoichiometry. High-quality single-phase ceramic samples prepared at 869 °C in oxygen at one atmosphere were annealed under various oxygen partial pressures and temperatures then rapidly quenched into liquid nitrogen to fix the value of δ. Tc was found to decrease monotonically with δ from a maximum of 92 K when δ=0, to a minimum of 30 K when δ=10. The normal-state carrier concentration has a one-to-one correspondence with δ. There is no significant difference between the oxygen unloading curves for δ as a function of temperature and pressure for Y2Ba4Cu7O15−δ and YBa2Cu3O7−δ; i.e., the unloading in the latter is twice that of the former. The volume change per oxygen vacancy is 3.1 Å per formula unit compared to 3.6 Å for YBa2Cu3O7−δ. The material remains orthorhombic for all values of δ.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Y2Ba4Cu7O15-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 92 | Pressure unresolved | onset |
| Er2Ba4Cu7O15-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 92 | Pressure unresolved | onset |
| YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 92 | Pressure not reported | unknown |
| YBa2Cu4O8 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 79 | Pressure not reported | unknown |
Similar papers
Pressure dependence of the superconducting transition temperature in the 94-K superconductor YBa2Cu3O7
similarity 0.95J. E. Schirber et al.
Source status unknown — claims are unverified
Structural chemistry and high-temperature superconductivity
similarity 0.95J. C. Phillips
Source status unknown — claims are unverified
Electronic structure of the high-temperature oxide superconductors
similarity 0.95Warren E. Pickett
Source status unknown — claims are unverified
Metal-insulator transition and superconductivity in Y1−xPrxBa2Cu3O7
similarity 0.95Yupeng Wang et al.
Source status unknown — claims are unverified
Effect of bismuth on high-Tc cuprate superconductors: Electronic structure of Bi2Sr2CaCu2O8
similarity 0.95Henry Krakauer & Warren E. Pickett
Source status unknown — claims are unverified
Defect structure of ferromagnetic superconducting RuSr2GdCu2O8
similarity 0.95O. I. Lebedev et al.
Source status unknown — claims are unverified