The specific heat and magnetic ordering at low temperature in superconducting Sm 1.85−xGd xCe 0.15CuO 4−δ

Abstract

The specific heat between 1.2K and 25K for the so-called n-type superconducting system Sm 1.85−xGd xCe 0.15CuO 4−δ (x=0.1, 0.3, 0.5, 0.75) has been measured and reported. Sharp peaks due to antiferromagnetic ordering of rare earth magnetic moments have been observed. The ordering temperature T M as well as superconducting transition temperature Tc decreases with increasing x, while the extra entropy corresponding to the peak increases at the same time. The superconductivity disappear when x exceeds 0.75, and the Tc(x) behavior has been found to be well fitted by an Abrikosov-Gor'kov expression.