G. Goll et H. Von Lohneysen, Point-contact spectroscopy on the heavy-fermion superconductor UPt3 in thenormal and superconducting states, PHYSICA C, 318, 1999, pp. 82-88
The heavy-fermion superconductor UPt3 has been investigated by point-contac
t spectroscopy in the normal and superconducting state with Pt as a normal-
metal counterelectrode. In the normal state well above T-c, the spectra, i.
e., the differential resistance dV/dI as a function of applied bias voltage
V, are determined by the thermal transport regime and can be described by
the heating model. Close to and below T-c diffusive or even ballistic trans
port through the contact yields voltage (i.e. energy) dependent non-lineari
ties of the point-contact characteristics. Andreev reflection (AR) of quasi
particles at the UPt3-Pt interface probes the superconducting energy gap an
d its complex angular structure. The results support that the anomalous sup
erconductivity in UPt3 can be attributed to the presence of a two-dimension
al (2D) order parameter (OP) with point and line nodes. (C) 1999 Elsevier S
cience B.V. All rights reserved.