Superconductivity with onset above 23° K in NbGe sputtered films

Sputtered films of nominal composition Nb₃Ge deposited onto hot substrates, of the type recently found by Gavaler to have superconductivity onsets at 22.3° K, have now been obtained with a maximum onset temperature of 23.2 ± 0.2° K and a transition width of ～ 1.2° K. The sputtering conditions necessary to achieve these results are discussed and suggest that the high T_c phase may be detrimentally affected by the presence of high energy particles present under normal sputtering conditions.