The partial substitution effects of br-anions for other halide anions (Cl, I) in the superconductor ET/sub 2/CuN(CN)/sub 2/Br

Summary form only given. By means of partial substitution of Br with Cl- or I-anions the mixed salts of ET/sub 2/CuN(CN)/sub 2/Br/sub 1-x/Hal/sub x/ (Hal = Cl, I) have been synthesized. The conducting properties of these salts have been studied. A new phase, /spl kappa/ET/sub 2/CuN (CN) /sub 2/Br/sub 0.5/Cl/sub 0.5/, which is a superconductor with T/sub c/=11.3 K, was found in the ET/sub 2/Cu(CN)/sub 2/Cl/sub x/Br/sub 1-x/ system. This superconductor is more three dimensional than pure bromide salt. The partial substitution of Br for I-anions leads to formation of mixed salts with the properties like those of pure iodide. However, in contrast to a latter, the salt ET/sub 2/CuN(CN)/sub 2/Br/sub 1-x/I/sub x/ (x = 0.1-0.15), exhibits superconducting transition with T/sub c/=3.5 K under pressure of about 0.3 kbar.