  Ion-implantation of normally insulating polymers offers an alternative to
depositing conjugated organics onto plastic films to make electronic circuits.
We used a 50 keV nitrogen ion beam to mix a thin 10 nm Sn/Sb alloy film into
the sub-surface of polyetheretherketone (PEEK) and report the low temperature
properties of this material. We observed metallic behavior, and the onset of
superconductivity below 3 K. There are strong indications that the
superconductivity does not result from a residual thin-film of alloy, but
instead from a network of alloy grains coupled via a weakly conducting,
ion-beam carbonized polymer matrix.

Superconductivity;Soft Condensed Matter