Search

Abstract: We report on pressure-dependent superconducting and transport properties of the quasi-two-dimensional organic superconductor β″-(ET)2SF5CH2CF2SO3. With increasing pressure both the superconducting transition temperature, T c, as well as the effective mass, m c, decrease monotonously. By assuming a direct relationship between m c and the superconducting coupling parameter λ, the pressure dependence of T c can be well described by the modified McMillan equation. For all pressures in the metallic state the resistance follows ρ = ρ 0 + AT 2 at low temperatures. The coefficient A, however, is found to be not proportional to as expected for a purely electronic origin of the T 2 behavior. [Copyright &y& Elsevier]

High-resolution specific-heat data of the organic superconductor κ-(ET)2Cu(NCS)2 (Tc=9.3 K) can reasonably well be described by strong-coupling BCS theory. In line with our previous results for three other organic superconductors the electronic contribution of the specific heat vanishes exponentially towards low temperatures providing evidence for a fully-gapped order parameter. The thermal conductivity κ of κ-(ET)2Cu[N(CN)2]Br increases strongly in the superconducting state below Tc=11.5 K indicating the substantial scattering of phonons by quasiparticles in the normal state. Down to the lowest temperatures (T≈0.25 K) no T3 dependence of κ is observed. [Copyright &y& Elsevier]