Cu63 Knight shifts in the superconducting state of YBa2Cu3O7−δ (Tc=90 K)

S. E. Barrett; D. J. Durand; C. H. Pennington; C. P. Slichter; T. A. Friedmann; J. P. Rice; D. M. Ginsberg

doi:10.1103/PhysRevB.41.6283

← Back to search

Cu63 Knight shifts in the superconducting state of YBa2Cu3O7−δ (Tc=90 K)

S. E. Barrett, D. J. Durand, C. H. Pennington, C. P. Slichter, T. A. Friedmann, J. P. Rice, D. M. Ginsberg

DOI 10.1103/PhysRevB.41.6283 · Physical Review B

T1

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

The authors have used Y89 NMR to measure the internal magnetic field of a sample of YBa2Cu3O7−δ (Tc=90 K) in the superconducting state to correct for the effects of the Meissner shielding currents. They used this information to separate the magnetic-shift tensor into orbital (chemical-shift) and spin (Knight-shift) contributions. They find that the temperature dependence of the chain Cu Knight shift fits the classic Yosida function of weak-coupling, orbital-s-state, spin-singlet BCS theory. For the planes, the Knight shift also requires a spin singlet, but with a strong-coupling Yosida function. The best fit is for an orbital s state, but an orbital d state is also possible. They find a zero-temperature gap Δ(0) of 1.76kBTc for the chains. For the planes, Δ(0) can range from 1.9kBTc to 3.1kBTc.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	unknown