The effect of Ag doping on the low temperature specific heats ofNd 1.85Ce 0.15CuAg xO 4− y

Abstract

The specific heat measurements were performed in the temperature range 2K<T<25K for a series of Nd 1.85Ce 0.15CuAg x O 4− y where X=0, 0.1 and 0.2. The resistivity data showed that Ag doping in Nd 1.85Ce 0.15CuO 4− y did not make marked change in superconducting transition temperature T c. A couple of features in the specific heat data of these compounds were noticed. First Ag doping in Nd 1.85Ce 0.15CuO 4− y slightly decreased the specific heat of Nd ions magnetic ordering for T<8K. Secondly the magnitudes of specific heat of Nd 1.85Ce 0.15CuAg x O 4− y were raised drastically by Ag doping. As the specific heats of electronic contributions and lattice contributions were estimated, the coefficients of electronic specific heat of Nd 1.85Ce 0.15CuO 4− y and Nd 1.85Ce 0.15CuAg 0.2 O 4− y were then calculated as ⋍ 10 mJ/mole K 2 and ⋍ 18mJ/mole K 2 respectively, and Debye temperature for the former was 175K and 160K for the latter.