Superconducting organic polymer films

A concept of producing superconducting composites. by means of reticulate doping of polymers with low molecular weight organic superconductors is presented. The obtained polycarbonate films contain around 2 wt.% of BEDT-TTF polyiodides in a form of continuous crystalline network. D.c. and microwave conductivity measurements demonstrate, that the as-obtained reticulate composites show semiconducting-type properties. After annealing at optimized conditions a dramatic change occurs and the composites become metallic in the entire temperature range due to a conversion of various phases of the BEDT-TTF polyiodides into the metallic and superconducting beta(t)-phase. The composites show the superconducting transition below 5 K, as evidenced by magnetoresistance measurements, indicating that the content of the beta(t)-phase microcrystals in the conducting network exceeds the percolation threshold.