Ginzburg-Landau parameter in YBa{sub 2}Cu{sub 3}O{sub 6.95} below the irreversibility temperature as measured by {mu}{sup +}SR in high magnetic fields

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.52.10569· OSTI ID:239385

Riseman, T M; Brewer, J H; Chow, K H; Hardy, W N; Kiefl, R F; Kreitzman, S R; Liang, R; MacFarlane, W A; Mendels, P; Morris, G D; Rammer, J; Schneider, J W ^[1]; Niedermayer, C ^[2]; Lee, S L ^[3]

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1. TRIUMF, Canadian Institute for Advanced Research and Department of Physics, University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada)
2. Fakultaet fuer Physik, Universitaet Konstanz, W-7750 Konstanz (Germany)
3. Physik-Institut der Universitaet Zuerich, CH-8057 Zuerich (Switzerland)

The vortex state of a type-II superconductor produces a distinctive {mu}{sup +}SR line shape with features determined by the average internal field {ital B}{sub {ital o}}, the magnetic penetration depth {lambda}, the superconducting coherence length {xi}, and the degree of disorder in the vortex lattice. Only in the high field regime ({lambda}{much_gt}{ital L}{gt}{xi}, where {ital L} is the intervortex spacing) do the vortex cores (of radius {approx}{xi}) occupy a large enough area that they are observable in the line shape as a high field cutoff. Our {mu}{sup +}SR measurements of the field distributions in a mosaic of single crystals of YBa{sub 2}Cu{sub 3}O{sub 6.95} in fields of 1.9, 4.1, 4.7, and 6.5 T ({bold B}{sub {ital o}}{equivalent_to}{ital c}) are the measurements by {mu}SR or NMR in a high-{ital T}{sub {ital c}} superconductor which show all the features of the line shape. We find {lambda}=0.15{plus_minus}0.01 {mu}m at 10 K and the Ginzburg-Landau parameter {kappa}{equivalent_to}{lambda}/{xi}=69.6{plus_minus}1.4 constant between 30 and 75 K; this is the only measurement to date of {kappa} in YBa{sub 2}Cu{sub 3}O{sub 6.95} below the irreversibility temperature. Due to disorder in the vortex lattice, either from pinning or from vortex fluctuations that are quasistatic on the time scale of {mu}{sup +}SR, the observed line shape is ``smeared`` relative to that predicted for a perfect lattice. From the degree of smearing, we estimate an upper limit of 5.5% for the rms deviation of individual vortices from their ideal positions.

• OSTI ID: 239385
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 14 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BARIUM OXIDES
COHERENCE LENGTH
COPPER OXIDES
GINZBURG-LANDAU THEORY
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
MAGNETIC FLUX
MUON SPIN RELAXATION
PENETRATION DEPTH
TEMPERATURE DEPENDENCE
TYPE-II SUPERCONDUCTORS
YTTRIUM OXIDES