APPARENT ABSENCE OF PAULI PARAMAGNETISM IN METALLIC POLYPARAPHENYLENE

The magnetic susceptibility of doped and undoped polyparaphenylene has been measured in the temperature range from 5 to 300 K by the static Faraday method and by ESR. In the static experiments, a Curie-like paramagnetism has been observed superimposed on a temperature-independent diamagnetic susceptibility. The Pauli paramagnetism of the doped samples is suprisingly small. Its upper limit has been determined to be only 2 multiplied by (times) 10** minus **7 emu cm**3/mole-carbon. The concentration of magnetic centers in the doped samples is several orders of magnitude smaller than the dopant concentration and does not scale with it. These results indicate a conduction mechanism involving nearly complete spin compensation of the charge carriers.