Unalloyed Titanium

Abstract

A study of the history of superconducting transition temperature measurement in pure Ti reveals the several difficulties which the experimentalist faces when attempting to make accurate determinations of low transition temperatures in pure substances. The principal difficulties encountered had to do in one way or another with sample purity and spurious effects associated with refrigeration and sample temperature determination. Such a study of course also emphasizes the fact that measurements which may be performed with extreme accuracy quite routinely today, were difficult and time-consuming three decades ago. The work up to 1953 has been summarized and discussed by EISENSTEIN [Eis54] who concluded that the most likely T_c for pure Ti was 0.387 K [Smi53] and that the wide discrepancies among the previously published results were attributable partly to differences in sample purity or condition and partly to lack of thermal equilibria between sample and paramagnetic salt capsule in those cases in which magnetic cooling was employed.