Both Fe3+ and Fe2+ ions occur in FeCl3-doped polyacetylene. At low dopant levels (2+ and Fe3+ ions are paramagnetic down to 4.2 K. At dopant levels >0.01 mole fraction, there is evidence from Mössbauer spectroscopy that Fe2+ ions associate into aggregates which are magnetically ordered below 25 K. Aggregate formation appears to correlate with high electrical conductivity.




URL: http://digitalcommons.calpoly.edu/phy_fac/153