ELECTRICAL AND STRUCTURAL-PROPERTIES OF KAPPA-TYPE ORGANIC CONDUCTOR

The electrical resistivities of organic metals with kappa-type molecular arrangements were examined. Superconducting transition temperature (T(c)) of alloy system kappa-[(ET)1-x(STF)x]2 Cu[N(CN)2]Br (ET=BEDT-TTF, STF=BEDT-DSeDTF) is rapidly depressed with increase of the doping amount of the asymmetric pi-donor STF. T(c) becomes lower than 1.6 K at x>0.25 but the system retains metallic state at least up to x=0.6. The characteristic resistivity maximum is smeared with increasing x. The metal-insultor transition of kappa-ET2Au(CN)2 at 70 K is suppressed by applying ''soft pressure'' of about 550 bar. The electrical properties and the crystal structures of kappa-MT2Cu[N (CN)2]X (MT=BMDT-TTF, X=Cl Br) were also examined. The crystal of kappa-MT2Cu[N(CN)2]X belongs to monoclinic system with space group Cc. The structure of anion sheet closely resembles that of kappa-MT2Cu[N(CN)2]X. The electrical resistivity decreases monotonously down to 2 K.