Novel Type of Career Generated System: Magnetic Investigations of TTF-Based Self-Doped Hydrogen-Bonding Conductor

Magnetic investigations, including static magnetic susceptibility and high-field electron spin resonance (ESR) measurements, were carried out for an organic conductor, (TTFCOO)[(NH4+1)(1-x)(NH3)(x)]. Anisotropic ESR parameters were determined for powder samples using a high-frequency W-band (93.9817 GHz) ESR spectrometer. The observed principal values of the g-tensor and quantum chemical calculation results indicate that the observed spin is distributed on quasi-hole-like TTF skeletons, and that the TTFCOO mainframe partially becomes a neutral radical. The temperature dependence of the spin susceptibility is well fitted with a Curie-Weiss term and an activation-type term, with the activation-type term dominant at high temperatures. The high absolute value of the spin susceptibility and the extremely small activation energy, Delta, indicate that a quasi-degenerate (metallic) state is stabilized in (TTFCOO)[(NH4+1)(1-x)(NH3)(x)], although the weakly temperature-dependent ESR linewidth indicates a localized characteristic. A novel type of carrier generation, self-doping, was discussed.