Ginzburg-Landau parameter in YBa2Cu3O6.95 below the irreversibility temperature as measured by μ+SR in high magnetic fields

T. M. Riseman*, J. H. Brewer, K. H. Chow, W. N. Hardy, R. F. Kiefl, S. R. Kreitzman, R. Liang, W. A. MacFarlane, P. Mendels, G. D. Morris, J. Rammer, J. W. Schneider, C. Niedermayer, S. L. Lee

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The vortex state of a type-II superconductor produces a distinctive μ+SR line shape with features determined by the average internal field Bo, the magnetic penetration depth λ, the superconducting coherence length ξ, and the degree of disorder in the vortex lattice. Only in the high field regime (λ rvortex spacing) do the vortex cores (of radius ξ) occupy a large enough area that they are observable in the line shape as a high field cutoff. Our μ+SR measurements of the field distributions in a mosaic of single crystals of YBa2Cu3O6.95 in fields of 1.9, 4.1, 4.7, and 6.5 T (Boc) are the measurements by μSR or NMR in a high-Tc superconductor which show all the features of the line shape. We find λ=0.15±0.01 μm at 10 K and the Ginzburg-Landau parameter κλ/ξ=69.6±1.4 constant between 30 and 75 K; this is the only measurement to date of κ in YBa2Cu3O6.95 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 μ+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.

Original languageEnglish
Pages (from-to)10569-10580
Number of pages12
JournalPhysical Review B
Volume52
Issue number14
DOIs
Publication statusPublished - 1995

Fingerprint

Dive into the research topics of 'Ginzburg-Landau parameter in YBa2Cu3O6.95 below the irreversibility temperature as measured by μ+SR in high magnetic fields'. Together they form a unique fingerprint.

Cite this