Specific heat of the ( [formula omitted], Gd) Al 2 system in the superconducting and normal state

Abstract

Specific heat measurements between 0.5 and 4.2°K are reported for the system ( La , Gd) Al 2 in both the superconducting and normal state. The observed specific heat jump at the superconducting transition temperature T c is in excellent agreement with the Abrikosov-Gor'kov (AG) theory. This is in accordance with the previously reported close correspondence of the T c vs. Gd concentration curve with the AG theory. Two very interesting features occur in the normal state specific heat. First, the Gd impurities cause a surprisingly strong enhancement of the electronic specific heat coefficient. Second, there is a large magnetic field dependent Schottky-like anomaly at low temperatures. This anomaly persists even in the superconducting state.