Controllable suppression of the unconventional superconductivity in bulk and thin-film Sr_{2}RuO_{4} via high-energy electron irradiation

Abstract

In bulk Sr_{2}RuO_{4}, the strong sensitivity of the superconducting transition temperature T_{c} to nonmagnetic impurities provides robust evidence for a superconducting order parameter that changes sign around the Fermi surface. In superconducting epitaxial thin-film Sr_{2}RuO_{4}, the relationship between T_{c} and the residual resistivity ρ_{0}, which in bulk samples is taken to be a proxy for the low-temperature elastic scattering rate, is far less clear. Using high-energy electron irradiation to controllably introduce point disorder into bulk single-crystal and thin-film Sr_{2}RuO_{4}, we show that T_{c} is suppressed in both systems at nearly identical rates. This suggests that part of ρ_{0} in films comes from defects that do not contribute to superconducting pairbreaking and establishes a quantitative link between the superconductivity of bulk and thin-film samples.