Abstract
The superconducting transition temperatures and critical fields of three wires of 99.9+percent pure tantalum, taken from the same spool, have been investigated to find the effect of annealing and gas content. Annealing the metal at very high temperatures raised the transition temperature from 4.156 to 4.32°K and lowered the initial slope of the critical magnetic field from 1360 to 600 gausses per degree. Much sharper transitions were observed for the annealed specimens. The effect of absorbed gas was slight. Spontaneous fluctuations of resistance on the transition into superconductivity were observed. The effect of the specimen current on the critical field was studied in one of the annealed specimens.

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