Tunneling Spectra in NbSe 3 ./I/Pb junctions

Abstract

NbSe₃, goes throught two phases transition inducing SDW states for T₁ = 149 K and T₂ = 59 K. These two transitions bring a partial condensation at Fermi level, the low temperature conductivity being always of metallic type. The evaluation of the width of the “gap” cannot be done simply. We employed this word “gap” althought it is incorrect here. Tunneling effect has permitted us to obtain an estimation of this “gap” for P=l bar and P=1 Kbar. We have kept tunneling spectra only for T < T₂. For T₁ > T > T₂, the width of the “gap” and thermal broadening are such that a measure is too imprecise. We have used the lead superconductivity as a test of good tunneling devices.