Interplay of self-doping and disorder in epitaxial Bi2Sr2Can-1Cun-1O2n+4+x(n = 1, 2) thin films under heavy-ion irradiation

We propose a novel mechanism for the modification of T-c in Bi2Sr2Can-1CunO 2n+4+x epitaxial thin films (2212 and 2201) under energetic heavy-ion irrad iation. By irradiating films with various oxygen content, we show from the temperature dependence of the resistance that irradiation always produces a doping effect superimposed on the damage caused to the sample. The effect is larger in 2201 than in 2212 thin films. The T-c decrease observed by irr adiating optimally doped films is partially due to this doping effect. Irra diation of semiconducting samples restores metallic superconducting behavio r