SPIN SUSCEPTIBILITY IN POLYANILINE - TEMPERATURE AND DOPING DEPENDENCE

Using a special electrochemical cell compatible with an ESR variable temperature insert, the temperature dependence of the spin susceptibility of polyaniline films has been measured for different doping levels. It is shown that in the conducting Emeraldine Salt the spin susceptibility decreases, with in particular zero Pauli susceptibilty. The data of the spin susceptibility versus doping are compatible with a polaron / bipolaron equilibrium, with a polaron concentration being essentially temperature independent.