Abstract
The critical field Hc2 was measured for a Pb-40 at.%-Bi alloy in porous-glass samples with pore diameters in the range 20-60 Å. Werthamer et al. have calculated Hc2, including the effect of electron paramagnetism and spin-orbit scattering. This theory fits the data for the 32- and 60-Å samples, giving the spin-flip scattering length of the order of the grain diameter. For the 20-Å samples the theory does not fit the results. It is suggested that the behavior of this sample is largely "one dimensional."