SPATIALLY-RESOLVED TUNNELING SPECTROSCOPY OF SUPERCONDUCTING WIRES WITH ARTIFICIAL PINNING CENTERS

We used scanning tunneling microscopy and spectroscopy to study with n anometer resolution the spatial variation of superconductivity in the vicinity of the interface between normal and superconductor regions. T he samples were novel superconducting wires consisting of ordered arra ys of sub-micron diameter normal metal filaments, either Cu or Nit emb edded in a NbTi superconducting matrix. By taking topographic images s imultaneously with current-voltage curves, we obtain information about the local quasi-particle density of states on both sides of the inter face. (C) 1998 American Institute of Physics.