title: Huge critical current density and tailored superconducting anisotropy in SmFeAsO₀.₈F₀.₁₅ by low-density columnar-defect incorporation.
abstract: Iron-based superconductors could be useful for electricity distribution and superconducting magnet applications because of their relatively high critical current densities and upper critical fields. SmFeAsO₀.₈F₀.₁₅ is of particular interest as it has the highest transition temperature among these materials. Here we show that by introducing a low density of correlated nano-scale defects into this material by heavy-ion irradiation, we can increase its critical current density to up to 2 × 10⁷ A cm⁻² at 5 K--the highest ever reported for an iron-based superconductor--without reducing its critical temperature of 50 K. We also observe a notable reduction in the thermodynamic superconducting anisotropy, from 8 to 4 upon irradiation. We develop a model based on anisotropic electron scattering that predicts that the superconducting anisotropy can be tailored via correlated defects in semimetallic, fully gapped type II superconductors.
authors.affiliation: Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: L
authors.initials: L
authors.lastname: Fang
authors.forename: Y
authors.initials: Y
authors.lastname: Jia
authors.forename: V
authors.initials: V
authors.lastname: Mishra
authors.forename: C
authors.initials: C
authors.lastname: Chaparro
authors.forename: V K
authors.initials: VK
authors.lastname: Vlasko-Vlasov
authors.forename: A E
authors.initials: AE
authors.lastname: Koshelev
authors.forename: U
authors.initials: U
authors.lastname: Welp
authors.forename: G W
authors.initials: GW
authors.lastname: Crabtree
authors.forename: S
authors.initials: S
authors.lastname: Zhu
authors.forename: N D
authors.initials: ND
authors.lastname: Zhigadlo
authors.forename: S
authors.initials: S
authors.lastname: Katrych
authors.forename: J
authors.initials: J
authors.lastname: Karpinski
authors.forename: W K
authors.initials: WK
authors.lastname: Kwok