Anisotropic Vortex Pinning in Single Crystal FeSe

ORAL

Abstract

Iron-based superconductors are known for their complex interplay between magnetic, nematic, and superconducting order. FeSe is an iron-based superconductor with a structural transition at 90 K without the appearance of magnetic ordering. The lack of magnetic order allows us to probe the superconducting transition of an iron-based superconductor from a purely nematic phase. We study single crystal FeSe using a scanning SQUID microscope that has both a field coil to apply a local magnetic field and a pickup loop to measure the vortex response. We model the effect of the SQUID geometry on vortex motion in an anisotropic pinning potential and find that SQUID orientation has a significant effect. Our initial findings suggest that that the pinning potential anisotropy aligns with twin domain boundaries produced by the structural transition. We also check for correlation between spatial variation in diamagnetic response and in anisotropy. These studies will help elucidate whether the relationship between nematic and superconducting order in these materials is competing or enhancing.

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Presenters

  • Irene Zhang

    Department of Applied Physics, Stanford University, Stanford, California 94305, USA, Stanford University

Authors

  • Irene Zhang

    Department of Applied Physics, Stanford University, Stanford, California 94305, USA, Stanford University

  • Logan Bishop-Van Horn

    Stanford University

  • Johanna Palmstrom

    Stanford University

  • John Robert Kirtley

    Stanford University

  • Yusuke Iguchi

    Department of Applied Physics, Stanford University, Stanford, California 94305, USA, Stanford University

  • Ian R Fisher

    Physics, Stanford University, Applied Physics, Stanford University, Stanford University, Pulsed Field Faclity, National High Magnetic Field Laboratory

  • Kathryn Ann Moler

    Department of Applied Physics, Stanford University, Stanford, California 94305, USA, Stanford University, Physics and Applied Physics, Stanford University