SUPPRESSION OF INSULATING STATE IN (BETS)(2)FECL4 BY MAGNETIC-FIELD

We report on the magnetotransport properties, up to 37 T, of the first organic conductor containing magnetic Fe3+ ions, lambda-(BETS)(2)FeCl 4, where BETS is bis(ethylenedithio)tetraselenafulvalene. The previous ly reported very sharp metal-insulator phase transition, which occurs at 8 K under ambient pressure, is suppressed when applying magnetic fi elds > 10 T. This unusual phenomenon may be connected to a field-induc ed ferromagnetic ordering of the Fe3+ ion moments. This could result i n some kind of ''evaporation'' of the previously condensed carriers, i nto a field-restored highly conducting state (FRHCS). In this ground s tate, angular dependence of the magnetoresistance is observed for curr ent flowing perpendicularly to the best-conduction c axis.