Superconductivity in the Zr-Rh-H(D) system

Measurements were made of the effect of hydrogen (deuterium) on the superconducting transition temperature of Zr-Rh alloys. The superconducting transition temperature of the alloys without hydrogen was found to depend on the different metallurgical phases present and not on the mean electron-to-atom ratio. The superconducting transition temperature of alloys with high rhodium contents (>10 at.% Rh) shows an initial linear decrease with increasing hydrogen concentration; with further addition of hydrogen the transition temperature falls rapidly below 4.2 K. However, the transition temperature of alloys with low rhodium contents is enhanced by the addition of small amounts of hydrogen apparently because of precipitation of the Zr2Rh phase. Further increase in the hydrogen concentration causes a decrease in the transition temperature and eventually results in the disappearance of superconductivity. For a given concentration the observed superconducting transition temperature was in general found to be greater for the deuterated alloys than for the corresponding hydrogenated alloys, indicating that deuterium is less effective than hydrogen in reducing the transition temperature of the Zr-Rh alloys. (Auth.)