Influence of additions of growth and superconducting properties of A-15 diffusion layers

In superconducting single-core A 15-diffusion-layer produced by the bronze-process the effect of small amounts of additions of Al, Ga, In, Si, Ge, Au and Ag in the bronze on layer formation, transition temperature and critical current were investigated. Addition of 0.5 at. % Ge or Si decrease the A 15-layer thickness by formation of Niobium-Germanide or -Silicide. The same content of Al or Ga increases the A 15-layer thickness. Amounts of gold and silver have no influence on the formation of the A 15-layer. The transition temperature is increased by addition of 0.8 wt. % Al or 0.5 wt. % Ge or 0.2 wt. % Si to the bronze, whilst the addition of Gallium decreases the transition temperature compared with the layer produced by the binary bronze and niobium.