Resistive transition to the superconducting state in α-(BEDT-TTF)2NH4Hg(SCN)4 under parallel magnetic fields

The resistive transition in two-dimensional superconductor α-(BEDT-TTF) 2 NH 4 Hg(SCN) 4 was studied under magnetic fields applied precisely parallel to the plane. This enables to suppress the effect of the orbital pair breaking and that of the vortex dynamics for the in-plane resistance measurement. At low temperatures ( 1.8 T). a hidden superconducting state where the resistivity is insensitive to temperature remains up to 5.5 T.