Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

• DOI: 10.1038/ncomms3655
• Publication Date: 2013-11-05T11:15:10Z
• Authors: L. Fang; Y. Jia; V. Mishra; C. Chaparro; V. K. Vlasko-Vlasov; A. E. Koshelev; U. Welp; G. W. Crabtree; S. Zhu; N. D. Zhigadlo; S. Katrych; J. Karpinski; W. K. Kwok
• Keywords: MPBH; 0103 physical sciences; 7. Clean energy; 01 natural sciences

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.