REENTRANT MEISSNER EFFECT IN THE ORGANIC CONDUCTOR K-(BEDT-TTF)2CU[N(CN)2]CL UNDER PRESSURE

Metallic kappa-(BEDT-TTF)2Cu[N(CN2]Cl turns semiconducting and insulat ing at low temperatures and ambient pressure and enters a ferrimagneti clike state below 20 K. Under hydrostatic pressure (p congruent-to 300 bar), previous investigations have shown that the metallic state can be stabilized and that reentrant superconducting behavior can be obser ved (by means of resistivity measurements) in a rather wide pressure r ange. By means of dc susceptibility measurements, we show that reentra nt volume superconductivity actually exists only in a narrow critical pressure range. In contrast to previously found reentrant superconduct ors, this material does not contain rare-earth magnetic moments.