Osaka City University Department of Material Science, Graduate School of Science 3-3-138 Sugimoto Sumiyoshi-ku, Osaka-shi 558-8585 Japan 3-3-138 Sugimoto Sumiyoshi-ku, Osaka-shi 558-8585 Japan
Japan Advanced Institute of Science and Technology Center for New Materials 1-1 Asahidai Tatsunokuchi-cho, Nomi-gun, Ishikawa 923-1292 Japan 1-1 Asahidai Tatsunokuchi-cho, Nomi-gun, Ishikawa 923-1292 Japan
Tokyo Metropolitan University Department of Chemistry, Graduate School of Science 1-1 Minamiosawa Hachioji-shi, Tokyo 192-0397 Japan 1-1 Minamiosawa Hachioji-shi, Tokyo 192-0397 Japan
The effect of thermal treatment on the electrical conductivity was studied for a quasi-one-dimensional organic conductor,
(DIMET)2I3 (DIMET=dimethyl(ethylenedithio)tetrathiafulvalene). After heating the samples up to a temperature between 340 and 370 K,
the electric resistivity was measured at low temperature down to 2 K and under pressure up to 1.6 Gpa. (DIMET)2I3 shows irreversible decrease in the electric resistivity between 350 and 356 K on heating. It was found that the heating above
350 K suppresses the spin-density-wave transition at 40 K and another metal-insulator transition appears at 18 K.