SYSTEMATIC INVESTIGATION OF ELECTRONIC-STRUCTURE IN BEDT-TTF BASED ORGANIC SUPERCONDUCTORS WITH T(C) ABOVE 10-K - KAPPA-(BEDT-TTF)2X (X=CU(NCS)2, CU[N(CN)2]BR, AND CU(CN)[N(CN)2])

The electronic structure of the title superconductors has been investigated by electrical resistivity, complex susceptibility, and electron paramagnetic resonance (EPR) measurements. The superconducting properties (pressure dependence of T(c), magnetic penetration depth, upper critical field, and so on) of these three salts are similar to each other, while transport properties in the normal state have shown a large variety in the temperature dependence. In order to clarify the electronic structure in the normal state, the EPR parameters, the spin susceptibility (chi(spin)), and the linewidth (DELTAH(pp)), are compared. An anomalous temperature dependence of the g-value has been observed below 150 K in the Cu(NCS)2 and Cu(CN)[N(CN)2] salts.