Field-Restored Highly Conducting State in λ-BETS₂FeCl₄ and λ-BETS₂FeBr_{0. 6}Cl_{3. 4} under Pressure

抄録

Magnetoresistance measurement of λ-BETS₂FeCl₄ and λ-BETS₂FeBr_{0. 6}Cl_{3. 4} were performed under pressure. λ-BETS₂FeBr_{0. 6}Cl_{3. 4} showed a sharp metal-insulator (MI) transition at 13. 7K under ambient pressure, which is 5. 2K higher than the MI transition temperature (T_MI) of λ-BETS₂FeCl₄. Under magnetic field, T_MI of λ-BETS₂FeBr_{0. 6}Cl_{3. 4} was almost constant up to 12 T. But at high pressure, λ-BETS₂FeBr_{0. 6}Cl_{3. 4} showed the field-restored highly conducting state (FRHCS). Magnetic susceptibility measurement of λ-BETS₂FeBr_{0. 6}Cl_{3. 4} showed no clear indication of antiferromagnetic transition at least down to 0. 1 T for the magnetic field parallel to the c axis.