TRANSPORT PROPERTIES OF ORGANIC CONDUCTOR (BEDT-TTF)(2)KHG(SCN)(4): I. RESISTANCE AND MAGNETORESISTANCE ANOMALY

The electrical resistance of the single crystalline organic salt (BEDT-TTF)2KHg(SCN)4 has been measured at temperatures down to 0.5 K and under magnetic fields up to 13 T. The zero-field resistance decreases almost monotonously with decreasing temperature down to 9-10 K and then exhibits a step-like anomaly accompanying the 30-40% resistance drop around below Ta=8 K. Under fields perpendicular to the conducting a-c plane, the resistance below Ta is so enhanced that an upturn in the temperature-dependent resistance appears and the resistance, for example, at 13 T and 0.5 K, becomes higher by a factor of 12 than the resistance at Ta and H=13 T. This anomalous magnetoresistance is never observed under fields precisely aligned parallel to the a-c plane. The dc magnetic susceptibility shows a broad maximum at Ta, which seems to be an evidence that weak anti-ferromagnetic correlations like spin-density-wave ordering takes place among p(p{cyrillic}) electrons itinerating in the metallic states. © 1990.