Magnetic field dependence of the magnetic susceptibility and the specific heat of the doped plasticizedpolyaniline (PANI-DB3EPSA)0.5

Abstract

Specific heat, magnetization and electron spin resonance (ESR) dataobtained from a self-standing film of the doped plasticized polyaniline(PANI-DB3EPSA)0.5 are shown. No long range magnetic order has been observed at zero magnetic field, above2 K. For a magnetic field of 3.3 kOe applied perpendicular to the plane of thefilm, a clear signature of an induced ordered state can be seen in the specificheat data and ESR also reveals this antiferromagnetic order. An electroniccontribution is detected from ESR, magnetization and specific heat; however, forT ≤ 5 K, the specific heat data show the existence of a gap. Magnetization data also show a lowtemperature dominant Curie behaviour which cannot be seen from ESR, probablydue to a very large linewidth, suggesting short range correlations among spin1/2 polarons.