title: Suppression of the critical temperature of superconducting NdFeAs(OF) single crystals by Kondo-like defect sites induced by alpha-particle irradiation.
abstract: We report the effect of alpha-particle irradiation on the reduction of the critical temperature T{c} of a NdFeAs(OF) single crystal. Our data indicate that irradiation defects cause both nonmagnetic and magnetic scattering, resulting in the Kondo-like excess resistance Delta rho(T) proportional to lnT over 2 decades in temperatures above T{c}. The critical density of magnetic irradiation defects which suppresses T{c} is found to be much higher than those for cuprates and multiband BCS superconductors. We suggest that such anomalously weak pair breaking by irradiation defects indicates that magnetic scattering in pnictides is coupled with pairing interactions mediated by spin fluctuations.
authors.affiliation: National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
authors.forename: C
authors.initials: C
authors.lastname: Tarantini
authors.forename: M
authors.initials: M
authors.lastname: Putti
authors.forename: A
authors.initials: A
authors.lastname: Gurevich
authors.forename: Y
authors.initials: Y
authors.lastname: Shen
authors.forename: R K
authors.initials: RK
authors.lastname: Singh
authors.forename: J M
authors.initials: JM
authors.lastname: Rowell
authors.forename: N
authors.initials: N
authors.lastname: Newman
authors.forename: D C
authors.initials: DC
authors.lastname: Larbalestier
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.forename: Ying
authors.initials: Y
authors.lastname: Jia
authors.forename: Hai-Hu
authors.initials: HH
authors.lastname: Wen