J. Phys. I France
Volume 4, Numéro 1, January 1994
Page(s) 159 - 166
DOI: 10.1051/jp1:1994104
J. Phys. I France 4 (1994) 159-166

High-field magnetotransport of organic conductors (BEDT-TTF) 2TlHg(XCN) 4 With X = S and Se

M. V. Kartsovnik1, D. V. Mashovets2, D. V. Smirnov2, V. N. Laukhin3, A. Gilewski4, 5 and N. D. Kushch3

1  Institute of Solid State Physics, Chernogolovka, MD, 142432 Russia
2  A. F. loffe Physical Technical Institute, St-Petersburg, 194021 Russia
3  Institute of Chemical Physics, Chernogolovka, MD, 142432 Russia
4  MAG-NET Laboratory, ul. Gajowicka 95, 53-529 Wroclaw, Poland
5  International Laboratory of Strong Magnetic Fields and Low Temperatures, ul. Gajowicka 95, 53-529 Wroclaw, Poland

(Received 26 July 1993, accepted 3 September 1993)

High field magnetoresistance of layered organic metals (BEDT-TTF) 2TlHg(XCN) 4 with X = S and Se has been studied using pulsed magnetic fields. Sharp negative slope and strong hysteresis of the magnetoresistance of (BEDT-TTF) 2TlHg(XCN) 4 found between about 11 and 27 T suggest a first-order phase transition to occur at those fields. Two different types of angular magnetoresistance oscillations corresponding most likely to different electronic states are observed in the low- and high-field phases, respectively. In contrast, the classical magnetoresistance of the salt with X = Se is found to be smoothly growing with the field increase. The obtained results are compared with those reported earlier on the (BEDT-TTF) 2MHg(SCN) 4 salts with M = K and NH 4 and discussed in the framework of the model proposed recently for the low-temperature electronic state of (BEDT-TTF) 2TlHg(SCN) 4.

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