Étude expérimentale de la chaleur spécifique du Rhenium

Abstract

The atomic heats of rhenium, in the normal and. superconducting states, have been determinedfrom 1,2 up to 24°K. The normal state atomic heat can be represented between 1,2 and 5°K by Cn = ɣT + 1944 (T/θD)3 with ɣ = (2,257 ± 0,026).10-3 joule • (at. gr.)-1. deg.-2 and θD = 407,4 ± 10,4° K. The electronic contribution to the atomic heat of the metal in the superconducting state can be represented below Tc = 1,699°K by Ces /ɣTc — a exp (— bTc/T) with a = 11,68 and b = 1,64 ; such an exponential relation is consistent with theory involving a gap in the spectrum of available energy levels. The entropy difference Sn — S s was found to vanish to within 4,7 % ; this. small deviation could be attributed to incorrect values of a and b used in the extrapolation to 0°K of the exponential relation. The critical field values deduced from the corrected Sn — Ss curve lead to H0 = 196 gauss but show deviation from the parabolic relation which can amount to 0,03 H0.