THERMODYNAMIC PROPERTIES OF THE ORGANIC SUPERCONDUCTOR KAPPA(L)-(ET)(2)AG(CF3)4-CENTER-DOT-TCE

We present specific-heat, magnetization, and ac-susceptibility measure ments of the recently discovered organic superconductor kappa(L)-(ET)( 2)Ag(CF3)(4) . TCE, where ET (=BEDT-TTF) stands for bisethylenedithio- tetrathiafulvalene and TCE is the neutral solvent 1,1,2-trichloroethan e. We observed a very large anisotropy of the critical field B extrac ted from ac-susceptibility data in accord with the enhanced ET-layer s eparation due to the large anions. The strong frequency dependence of B reveals the weak pinning forces in the material. Magnetization and specific-heat, C, measurements prove the bulk effect of superconductiv ity. The linear coefficient of C is gamma approximate to 50 mJ/molK(2) which is a factor 9 larger than expected from a free-electron picture . Indications for strong coupling are found.