J. Phys. IV France
Volume 114, April 2004
Page(s) 463 - 466

J. Phys. IV France
114 (2004) 463
DOI: 10.1051/jp4:2004114108

New ambient pressure organic superconductor with Tc= 8.1  K: (EDT-TTF)4Hg $_{3-\delta}$I 8

R.N. Lyubovskaya1, 1, E.I. Zhilyaeva1, S.A. Torunova1, G.A. Mousdis2, G.C. Papavassiliou2, J.A.A.J. Perenboom3, Pesotskii1, 3, 4 and R.B. Lyubovskii1, 3, 4

1  Institute of Problems of Chemical Physics RAS, Chernogolovka, MD 142432, Russia
2  Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 11635, Greece
3  Nijmegen High Field Magnet Laboratory, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
4  International Laboratory of High Magnetic Fields and Low Temperatures, Wroclaw 53-529, Poland

New ethylenedithiotetrathiafulvalene (EDT-TTF)-based radical cation salts with mercury containing anions of different size and shape have been isolated and studied. Among these compounds the new ambient pressure organic superconductor (EDT-TTF) 4Hg $_{3-\delta}$I 8, $\delta \sim $0.1 $\div $0.2, with T c=8.1K has been synthesized. Depending on a EDT-TTF/HgI 3-/HgI 2 ratio, electrochemical crystallization of EDT-TTF affords either hexagonal (EDT-TTF) 4Hg $_{3\pm
\delta }$ I 8, ( $\delta \sim $0.1 $\div $0.2) or rectangular (EDT-TTF) 2HgI 3 crystals. Three types of hexagonal crystals were certified using conductivity measurements: the crystals with superconducting temperature T c=8.1K under ambient pressure (1), those undergoing a superconducting transition at 5 <T c<8K under p $\sim $0.3 kbar (2), and the crystals undergoing a metal-insulator transition below 35K (3). Key words. Organic superconductors, transport measurements, conductivity

© EDP Sciences 2004