ROLE OF POLARONS IN THE ANTIFERROMAGNETIC BEHAVIOR OF POLY(3-DODECYLTHIOPHENE)

A mathematical model was suggested and tested to elucidate the antifer romagnetic behaviour of temperature dependence of the magnetic suscept ibility of poly(3-dodecylthiophene) (PDDT) which takes advantage of th e physical properties of polarons and bipolarons. It has been found th at the responsibility for the antiferromagnetic behaviour of temperatu re dependence of the magnetic susceptibility of PDDT is the conversion of polarons to bipolarons, rather than the presence of several crysta lline sublattices of the polymer with different orientations of magnet ic moments. The antiferromagnetic character is caused by paramagnetic polarons, the number of which decreases with lowering temperature. The proposed model was verified, with good results also for other conduct ive polymers exhibiting antiferromagnetic properties known from the li terature.