Coexistence of Magnetism and Superconductivity in Separate Layers of Iron-Based Superconductor Li<sub>1-x</sub>Fe<sub>x</sub>(OH)Fe<sub>1-y</sub>Se

ORAL

Abstract

The family of compounds of general formula Li1-xFex(OH)Fe1-ySe, consisting of alternating Fe1-ySe and Li1-xFex(OH) layers, have been found to superconduct with Tc’s of ≈ 40 K. The hydroxide layer, containing roughly 20 % substitution of Li for Fe, has been shown to display magnetism well below the superconducting transition in the region of 10 K. This has been alternately reported as an ordering of the hydroxide layer Fe moments ferromagnetically and antiferromagnetically. Our study elucidates this magnetism by taking advantage of the flexible synthesis of these compounds allowing investigation of superconducting and non-superconducting variants in an effort to disentangle magnetism form superconductivity. Utilizing static and dynamic magnetometry, measurement of heat capacity and muon spin relaxation we propose the magnetism of the hydroxide layer to be glass-like and coexist with superconductivity.

PRB, 95, 134419 (2017)

*This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) (Grant No. ER/M020517/1), the Leverhulme Trust (Grant No.RPG-2014- 221), and the Oxford Centre for Applied Superconductivity. Work at the Diamond Light Source was funded by Allocation No. EE13284.

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Presenters

  • Craig Topping

    • School of Physics and Astronomy, University of St Andrews

Authors

  • Craig Topping

    • School of Physics and Astronomy, University of St Andrews

  • Franziska Kirschner

    • University of Oxford
    • Oxford University
    • Department of Physics, University of Oxford

  • Steve Blundell

    • University of Oxford
    • Department of Physics, University of Oxford
    • Physics, University of Oxford

  • Peter J. Baker

    • ISIS Facility, Rutherford Appleton Laboratory
    • ISIS Facility, Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0QX, UK.

  • Daniel Woodruff

    • Department of Chemistry, University of Oxford

  • Francesca Schild

    • Department of Chemistry, University of Oxford

  • Hualei Sun

    • Department of Chemistry, University of Oxford

  • Simon Clarke

    • Department of Chemistry, University of Oxford