ESR investigation of organic conductors (DTM-TTP)(TCNQ) (TCE) and (TMET-TTP)2(TCNQ)

Magnetic properties of the title compounds are investigated by ESR measurements, and from the temperature dependence of the g-values, the spin susceptibility is separated into donor and TCNQ contributions. For (DTM-TTP)(TCNQ) (TCE), the overall. spin susceptibility decreases gradually from room temperature to 200 K, and more rapidly below 200 K, indicating a gradual crossover from a metallic to nonmagnetic insulating state. For (TME-TTP)(2) (TCNQ), the spin susceptibility exhibits a gradual increase from room temperature to 50 K, followed by a rapid Curie-like increase that is attributed to the isolated TCNQ molecules. The donors remain paramagnetic even in the insulating state in accordance with the two-dimensional theta-type arrangement of the donor conducting sheet.