Performance of high temperature superconducting ceramic/thermoplastic polymer composites

Abstract

Abstract A technique for preparing flexible composites by dispersing high Tc yttrium based superconductor filler in a polyethylene matrix with transition temperature of about 90 K has been developed. Susceptibility measurements demonstrated a high degree of field exclusion, indicating that the superconducting behavior is preserved in the yttrium barium copper oxide (YBa2Cu3O7-×) filler material. It is found that all the composites showed the diamagnetic transition at around 90 K, which is the same as that of the pure YBCO sample. The single transition for both the parent YBCO material and the composite samples indicates the dominant presence of isolated superconducting grains within such samples. A large drop in resistivity with increasing filler content is observed for all the ceramic-polymer systems investigated in this study. At low percentages of the filler, the composite behaves as an insulator with very low conductivity. No dc zero resistance transition is observed. The absence of zero resistance in these composites was presumably due to the absence of appropriate contacts between the superconducting grains and the lack of a conductive path necessary for a zero resistance transition to occur.