J. Phys. IV France 114 (2004) 297
The pressure-temperature phase diagram of pressure induced organic superconductors -(BDA-TTP) 2MCl 4 (M = Ga, Fe)E.S. Choi1, 1, D. Graf1, J.S. Brooks1, J. Yamada2 and M. Tokumoto3
1 National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
2 Dept. of Material Science, Graduate School of Science, Himeji Institute, Hyogo 678-1297, Japan
3 Natotechnology Institute, AIST, Tsukuba 305-8568 and JST-CREST, Kawaguchi 332-0012, Japan
We investigate the pressure-temperature phase diagram of -(BDA-TTP) 2MCl 4 ( M=Ga, Fe), which shows a metal-insulator (MI) transition around 120 K at ambient pressure. By applying pressure, the insulating phase is suppressed. When the pressure is higher than 5.5 kbar, the superconducting phase appears in both salts with Tc 3 K for M=Ga and 2.2 K for M=Fe. We also observed Shubnikov-de Haas (SdH) oscillations at high magnetic field in both salts, where the SdH frequencies are found to be very similar each other. Key words. organic superconductor, pressure, phase diagram.
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