New features in the microwave response of YBCO crystals: Evidence for a multi-component order parameter

H. Srikanth; Balam A. Willemsen; T. Jacobs; S. Sridhar; A. Erb; E. Walker; R. Flukiger

doi:10.1103/PhysRevB.55.R14733

paper

New features in the microwave response of YBCO crystals: Evidence for a multi-component order parameter

arXiv:cond-mat/9610032 · doi:10.1103/PhysRevB.55.R14733

Abstract

New features are reported in precision measurements of the complex microwave conductivity of high quality $Y B a_{2} C u_{3} O_{6.95}$ crystals grown in $B a Z r O_{3}$ crucibles. A third peak in the normal conductivity, $I ¨ _{1} (T)$ , at around $80 K$ , and enhanced pair conductivity $I ¨ _{2} (T)$ below $\sim 65 K$ are observed. The data are inconsistent with a single order parameter, and instead are indicative of multi-component superconductivity. Overall, these results point to the presence of multiple pairing interactions in $Y B a_{2} C u_{3} O_{6.95}$ and also provide a natural explanation to account for the low temperature $35 K$ conductivity peak observed in all $Y B a_{2} C u_{3} O_{6.95}$ crystals.

4 pages 4 figures, Revtex, multicols [to appear in Phys. Rev. B (Rapid Comm)]. Our preprints also available at http://sagar.physics.neu.edu/preprints.html