Studies in Superconductivity III. Sn, Cb, Ta, and Pb Wires

The electrical and magnetic properties (in fields of 0-80 oersteds) of Sn, Cb, Ta, and Pb wires of several diameters (25-250 microns) have been studied in the superconducting state. In addition x-ray powder photographs (made with copper $K\alpha$ radiation) have been taken of the wires studied. The experimental results obtained showed that a low resistance ratio, $\frac{R}{R_0}$ ($R_0=\mathrm{room}\mathrm{temperature}\mathrm{resistance}$), high transition temperature, and small transition range were always found together for a given metal. For lead the 25,127- and 254-micron wires studied, all exhibited a transition temperature of 7.20±0.01°K, a fact which is attributed to the similar crystalline character of these wires.