Nuclear Resonance Properties of YBa2Cu3O6+x Superconductors

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Science  01 Jun 1990:
Vol. 248, Issue 4959, pp. 1082-1087
DOI: 10.1126/science.248.4959.1082


Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) results for copper-63, oxygen-17, and yttrium-89 nuclei in the superconducting composition range of YBa2Cu3O6+x (0.4 ≤ x ≤ 1.0) are reviewed and interpreted. Copper NMR shift and susceptibility data, combined with a simple ionic model of local magnetic properties, yield a comprehensive analysis of the normal-state anisotropic susceptibility components and full characterization of the copper spin and orbital hyperfine couplings. Data on the spin-lattice relaxation time of these three nuclear species serve to characterize the highly correlated fermion dynamics in this system. Relaxation data from YBa2Cu3O7 (superconducting transition temperature Tc = 90 K) and oxygen-deficient samples of this material (Tc ∼60 K) have been analyzed in terms of meanfield models incorporating short-range antiferromagnetic order, giving a quantitative account of (planar) relaxation for these three nuclei in terms of a single dynamical susceptibility.