Energy gaps of ordered and disordered A15 ’’phases’’ in Nb3Ge measured by tunneling

Abstract
In electron tunneling measurements into high‐Tc getter‐sputtered Nb3Ge films, two energy gaps are clearly identified. The larger, 2Δ=7.8 meV, we associate with well‐ordered A15 material. The smaller, 2Δ∼1.0 meV, we suggest indicates the presence of very disordered material, because we cannot identify any known phase of the NbGe system with this low gap, and because a most interesting ’’phase’’ of Nb3Ge, with 2Δ=0.86 meV and Tc=3.06 K, was isolated by sputtering from the same target onto a cold (100−200 °C) substrate.