Superconducting Properties of CeRu₂

We have measured the specific heat and the magnetization in the superconducting mixed state of CeRu₂ at low temperatures and in high magnetic fields. We have clarified a rich variety of superconducting properties such as the temperature dependence of the electronic specific heat and Maki parameters κ₁, κ₂ and κ₃. From these experimental results, CeRu₂ is concluded to be of the BCS-type in superconductivity. Nevertheless, interesting is the magnetic field dependence of the electronic specific heat at 0.5 K, indicating a √H like behavior in low fields and a H-linear dependence in high fields up to the upper critical field of 50 kOe. This characteristic specific heat is discussed on the basis of a microscopic theory by Brandt et al.