Measurements of quenched-in resistivity in thin single crystal tungsten wires

Abstract

We have measured the electrical resistivities of a series of thin polycrystal and single-crystal tungsten wires annealed and quenched in both ultra-high vacuum and superfluid helium. For a given sample the quenched-in resistivities were very nearly the same for both ultra-high vacuum and superfluid quenches. We infer from this result that the quenched-in resistivities are not due either to quenohed-in helium atoms or to atmospheric contamination as recently suggested by Evans. On the other hand, the magnitude of the quenched-in resistivity varied somewhat from sample to sample. Measurements with an optical pyrometer suggest that this variation is not due primarily to differences in temperature of the samples just prior to quenching. Analysing both our data and other data recently published we conclude that impurities must play an important, but not yet adequately understood, role in determining the magnitude of the resistivity retained in quenched tungsten.