Differential-thermal analysis around and below the critical temperature Tc of various low-Tc superconductors: A comparative study

We present specific-heat data on the type-II superconductors V3Si, LuNi2B2C and NbSe2 which were acquired with a low-temperature thermal analysis (DTA) technique. We compare our data with available literature data on these superconductors. In the first part we show that the DTA technique allows for fast measurements while providing a very high resolution on the temperature scale. Sharp features in the specific heat such as at the one at the transition to superconductivity are resolved virtually without instrumental broadening. In the second part we investigate the magnetic-field dependence of the specific heats of V3Si and LuNi2B2C at a fixed temperature T=7.5K to demonstrate that DTA techniques also allow for sufficiently precise measurements of absolute values of cp even in the absence of a sharp phase transition. The corresponding data for V3Si and LuNi2B2C are briefly discussed.