Encouraging Superconductivity with Elemental Substitutions
Advanced techniques have revealed what happens to the magnetism in an iron-arsenide superconductor when some of the iron atoms are replaced by iridium. Substituting some iron atoms by transition metals (TM) such as cobalt, nickel, platinum and iridium suppresses the magnetic order of the non-superconducting parent phases of the iron pnictides, which promotes superconductivity. The way this happens remains one of the most intriguing puzzles in the field. A team of scientists has used x-ray resonant magnetic scattering at the DOE’s Advanced Photon Source to probe the local magnetic order associated with dilute iridium substitutions for iron in superconducting samples of Ba(Fe1−xIrx)2As2. These measurements show that the individual iridium are magnetically polarized at low temperatures, manifest the same magnetic order as the majority iron moments, and that this magnetically polarized state coexists microscopically with superconductivity in these samples. These findings reveal the interplay between magnetism and superconductivity in doped systems.
- M. P. M. Dean, M. G. Kim, A. Kreyssig, J. W. Kim, X. Liu, P. J Ryan, A. Thaler, S. L. Bud’ko, W. Straszheim, P. C. Canfield, J. P. Hill and A. I. Goldman, Magnetically polarized Ir dopant atoms in superconducting Ba(Fe1−xIrx)2As2. Physical Review B, 2012, 85, 140514. DOI: 10.1103/PhysRevB.85.140514 Editor’s Choice article.