Study of magnetic properties of copolymer of 3-dodecylthiophene and 2,3-R,R-thieno[3,4-b]pyrazine

The EPR spectroscopy and the measurement of AC magnetic susceptibility (χ), magnetization and of specific heat capacity were used to study magnetic properties of the copolymer (COP) of 3-dodecylthiophene (DDT) and 2,3-R,R-thieno[3,4-b]pyrazine (TTP). The copolymer exhibits antiferromagnetic properties at the Nèel temperature of ca. 38 K. At maximum complex, magnetic susceptibility achieved value of 6.5×10−6 m3 kg−1. That behaviour was ascribed to the heat-activated transitions of bipolarons to polarons, which are stimulated by conformational changes in the polymer chains of semi-crystalline regions existing in the polymer.