FIXED-SPIN-INDUCED ESR LINEWIDTH AND POLARON MOBILITY IN CONDUCTING POLYMERS

The relationship between the polaron mobility and the fixed-spin-induc ed ESR linewidth is verified experimentally in HCl-doped polyaniline i n which a controllable amount of Fe3+ paramagnetic ions have been inco rporated. The polaron mobility has been varied by (a) decreasing the t emperature, and (b) aging of the material. In both cases, the line bro adening has been compared to the de conductivity, and to the intrachai n spin-diffusion rate obtained from NMR measurements. The line broaden ing appears to be proportional to the spin-diffusion rate. implication s of this line-broadening mechanism are discussed, in particular conce rning the temperature dependence of the ESR linewidth.