Title :
Angular dependence of the symmetry of the order parameter in YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//
Author :
Gim, Y. ; Mathai, A. ; Black, R. ; Amar, A. ; Wellstood, F.C.
Author_Institution :
Center for Superconductivity Res., Maryland Univ., College Park, MD, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
Using a 4.2 K scanning SQUID microscope, we examined twinned thin-film YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO)-Ag-PbIn SQUIDs and measured the phase of the order parameter in the YBCO for 13 different tunneling angles. We have found that the order parameter in YBCO is time-reversal symmetric and shows a d(x/sup 2/-y/sup 2/)-pairing symmetry, provided the junctions are properly made. Detailed analysis of our data reveals that any time-reversal breaking component is less than 5%, which rules out states such as d(x/sup 2/-y/sup 2/)+ is or d(x/sup 2/-y/sup 2/)+ id/sub xy/.
Keywords :
SQUIDs; barium compounds; high-temperature superconductors; superconducting thin films; superconductive tunnelling; yttrium compounds; 4.2 K; YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//; YBa/sub 2/Cu/sub 3/O/sub 7/-Ag-PbIn; angular dependence; d(x/sup 2/-y/sup 2/)-pairing symmetry; order parameter phase; order parameter symmetry; scanning SQUID microscope; screened current response; time-reversal breaking component; time-reversal symmetry; tunneling angles; twinned thin-film YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta//-Ag-PbIn SQUIDs; Educational institutions; Josephson junctions; Microscopy; Phase measurement; Physics; SQUIDs; Superconducting transition temperature; Superconductivity; Tunneling; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
