Magnetic properties of transpolyacetylene films in the low-temperature region

The magnetic behavior of transpolyacetylene films is investigated experimentally in the temperature range 1.7-150 K using the Faraday method to directly measure their magnetic susceptibility and magnetization. Determinations are made of the Curie constant and of the spin state of neutral defects (solitons). The results obtained show that there is no interaction between spin moments down to 1.7 K. The free spin concentrations determined in this study are consistent with conductivity measurements assuming the formation of soliton levels at the center of the forbidden zone of this organic semiconductor.