Superconducting properties of noncentrosymmetric Nb0.18Re0.82 thin films probed by transport and tunneling experiments

Artikel i vetenskaplig tidskrift, 2016

Superconducting thin films of the noncentrosymmetric superconductor Nb0.18Re0.82 were successfully deposited by UHV sputtering technique. X-ray diffraction analysis indicated that the films are polycrystalline, with a preferential (nn0) orientation and the lattice parameter in agreement with the expected single alpha-Mn cubic phase. A detailed electrical characterization of the samples as a function of the thickness (3.5 nm <= d <= 142 nm) was performed both in the normal and in the superconducting states, revealing a well-established superconducting ordering, as well as an estimated value of the upper critical field, mu H-0(c2),comparable with the Pauli limit. Finally, the symmetry of the order parameter was probed by tunneling spectroscopy on Al/Al2O3/Nb0.18Re0.82 heterostructures, which provides evidence for a single s-wave superconducting gap.