Abstract
We have measured the transition temperature Tc, upper critical field Hc2 (T) and the resistivity above Tc, OTc, for thin films of electron beam co-evaporated Nb-Sn which were deposited as NboSn at various substrate temperatures, or off-stoichiometry, or with tertiary additions of Al or Zr. The Tc and Hc2 correlate with the resistivity, no matter how the materials were made. A maximum Hc2(0) of about 300 kOe occurs when OTc ∼ 30 μΩ-cm and the corresponding Tc ∼ 16 K; alsoc Hc2 shows no sign of Pauli limiting. © 1981 IEEE