paper

Superconducting gap and pair breaking in CeRu2 studied by point contacts

arXiv:cond-mat/0107113 · doi:10.1063/1.1399197

Abstract

The superconducting gap in a CeRu $_{2}$ single crystal is investigated by point contacts. BCS-like behavior of the gap $I^$ in the temperature range below T $_{c}^{*} <$ T $_{c}$ , where T $_{c}$ is the critical temperature, is established, indicating the presence of a gapless superconductivity region (between T $_{c}^{*}$ and T $_{c}$ ). The pair-breaking effect of paramagnetic impurities, supposedly Ce ions, is taken into consideration using the Scalski-Betbeder-Matibet-Weiss approach based on Abrikosov-Gorkov theory. It allows us to recalculate the superconducting order parameter $I^^{I^} \pm$ (in the presence of paramagnetic impurities) and the gap $I^^{P}$ (in the pure case) for the single crystal and for the previously studied polycrystalline CeRu $_{2}$ . The value 2 $I^^{P}$ (0) $\approx$ 2 meV, with 2 $I^^{P}$ (0) $/$ k $_{B}$ T $_{c} \approx$ 3.75, is found in both cases, indicating that CeRu $_{2}$ is a ``moderate'' strong-coupling superconductor.

4 pages incl. 3 figs., publ. in Fiz. Nizk. Temp. (http://fnte.ilt.kharkov.ua/list.html)