Published online by Cambridge University Press: 25 February 2011
We have measured the specific heat of κ-(BEDT-TTF)2Cu(NCS)2 from 4 to 14 K. The superconducting transition at 9.4 K is observed in zero applied magnetic field and in a field of 0.3 T. Both the magnitude of the change in Cp at Tc and the temperature dependence of Cp below Tc indicate a strong coupling superconductor. If the lattice specific heat is assumed to contain contributions due to the eighteen vibrational degrees of freedom, the phonon contribution to the specific heat in our temperature range can be represented by a Debye integral expression with a Debye temperature of 95 K. A model of collective modes suggesting the origin of the eighteen degrees of freedom is presented.