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

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

2331

Lastpage

2334

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;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.621706

Filename

621706