Institution: | a Chemistry and Materials Science Divisions, Argonne National Laboratory, Argonne, IL 60439, USA b Institut für Anorganische Chemie, Universität Köln, Greinstrasse 6, D-50939, Köln, Germany c Sandia National Laboratories, Albuquerque, NM 87185, USA |
Abstract: | We report the discovery of a second, higher-Tc superconducting organic charge-transfer salt derived from the electron-donor molecule BEDT-TTF (or ET), the novel organometallic anion Cu(CF3)4]?, and the neutral solvent molecule 1, 1, 2-trichloroethane (TCE). We have very recently reported that this charge-transfer system yields a new superconducting phase salt, L- (ET)2Cu(CF3)4·TCE, with inductive onset Tcrmc=4.0 K at ambient pressure. This phase salt ( denotes a particular packing arrangement of the ET organic donor molecules) is electrocrystallized in the habit of hexagonal plates. Crystals possessing a needle-like habit electrocrystallize simultaneously with these plates, and we find these needles to be a distinctly different superconducting phase with diamagnetic onset Tc=9.2±0.1 K at ambient pressure. On the basis of our experiments, we denote this new superconducting phase as H?(ET)2Cu(CF3)4·(TCE)x,X<1. |