Field-induced low-temperature anomaly in κ-(D8-BEDT-TTF)2Cu(NCS)2

The linear coefficient of thermal-expansion, τ(T), on a high-quality single crystal of the title compound reveals pronounced and strongly anisotropic phase-transition anomalies at Tc = 9.95 K. Application of magnetic fields perpendicular to the conducting planes leads to pronounced superconducting fluctuation effects and scaling behaviour in α(T,B). The latter enables us to separate an additional, field-induced anomaly in the superconducting state for B ≥ 3 T. Anomalous bahaviour remains also in fields B > Bc2 with a qualitative different phenomenology.