Evidence for complex superconducting order parameter symmetry in the low-temperature phase of UPt3 from Josephson interferometry.
We present data on the modulation of the critical current with applied magnetic field in UPt3-Cu-Pb Josephson junctions and SQUIDs. The junctions were fabricated on polished surfaces of UPt3 single crystals. The shape of the resulting diffraction patterns provides phase-sensitive information on the superconducting order parameter. Our corner junction data show asymmetric patterns with respect to magnetic field, indicating a complex order parameter, and both our junction and SQUID measurements point to a phase shift of pi, supporting the E(2u) representation of the order parameter.
Strand
J D
JD
Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. strand2@illinois.edu
Van Harlingen
D J
DJ
Kycia
J B
JB
Halperin
W P
WP