Synthesis and physical properties of (BEDT-TTF)/sub 2/H/sub 2/PO/sub 4/

Summary form only given. The current trend in studying the Fermi surface theoretically and experimentally in conducting salts of BEDT-TTF encourages us to fine tune the desired Fermi surface by varying the band filling in the hope of finding the relationship between density of states at the Fermi level, the bandwidth and the mass of the carriers to the superconducting critical temperature. Towards this goal a series of electrocrystallisation of BEDT-TTF was carried out with H/sub 2/PO/sub 4-/, HPO/sub 4//sup 2-/ and PO/sub 4//sub 3-/ in varying proportion to produce solid solutions. We report the synthesis and properties of the crystals of the first member (BEDT-TTF)/sub 2/H/sub 2/PO/sub 4/. It crystallises as shiny hexagonal plates belonging to the triclinic system, P1, a=17.737, b=7.927, c=6.514/spl Aring/, /spl alpha/=110.45, /spl beta/=95.42, /spl gamma/-88.69/spl deg/, V=854/spl Aribg//sub 3/. The electrical conductivity is /sol tilde/50Scm/sup -1/ at 295K with metallic behaviour to 1.5K; there is evidence of a transition /spl tilde/200K. The EPR linewidth changes by factor of four from 295 to 4K. The magnetic susceptibility and optical reflectivity will be also presented.