Transport and microwave properties of the metal-spine conductor Co(phthalocyaninato)I

Microwave conductivity and dielectric constant at 15 GHz are reported for the cobalt(II)-phthalocyaninato-iodide, Co(pc)I, metal-spine conductor. We also present the dc conductivity and the thermoelectric data down to 4 K. Above 100 K, the transport properties are nonmetallic and as the temperature is decreased a transition to an activated regime is observed around T50 K. In the same temperature range, the dielectric constant shows a stepwise variation. These data suggest, at high temperatures, a pseudogap picture related to disordered iodine chains and, at low temperatures, the opening of a real gap possibly due to the three-dimensional ordering of the same iodine chains.