Transport measurements of the heavy fermion superconductor CeCu2Si2 under pressure

Abstract

Superconducting and normal state properties of a single crystal of CeCu2Si2 have been investigated by resistivity measurements under hydrostatic pressure and magnetic field. The low temperature resistivity behaviour (ρ = ρ0 + AT2, which is observed up to a temperature TA) is considered within the self-consistent renormalized (SCR) spin fluctuation model. Contrary to the model predictions, the product AT2A increases on approaching the quantum critical point (QCP). The temperature dependence of the upper critical field is analyzed assuming strong coupling and an intermediate regime between the clean and dirty limits. Both the low temperature resistivity behaviour at high pressure and the parameters deduced from the fits of Hc2 point to a pressure induced decrease of the quasi-particle effective mass m*. The anisotropy of the initial slope of Hc2(T) and therefore that of the effective mass was found to change under pressure.