Local-field dependence of the {sup 17}O spin-lattice relaxation and echo decay rates in the mixed state of YBa{sub 2}Cu{sub 3}O{sub 7}
- Department of Physics and Materials Research Laboratory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States)
We find that the planar and apical {sup 17}O NMR spin-lattice relaxation rate (1/T{sub 1}) and the spin-echo decay rate (1/T{sub 2}) are spatially dependent in the mixed state of YBa{sub 2}Cu{sub 3}O{sub 7}. For both sites, 1/T{sub 1} and 1/T{sub 2} increase by a factor of 2 to 3 for nuclei close to the vortex cores. The data suggest that fluctuating fields from the low-frequency vibrations of the vortex lattice give rise to the similar echo decay observed at both sites. These vibrations also dominate 1/T{sub 1} for both sites below T(less-or-similar sign)25 K. Above this temperature, the planar 1/T{sub 1} is dominated by spin-flip scattering with delocalized quasiparticles associated with the nodes in the superconducting gap showing that the position dependence arises from the effect of the supercurrents on the quasiparticle energy spectrum. (c) 2000 The American Physical Society.
- OSTI ID:
- 20217228
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 62, Issue 5; Other Information: PBD: 1 Aug 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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