Small Angle Neutron Scattering Studies of the Vortex Lattice in CeCoIn$_5$ with $H \perp c$

ORAL

Abstract

We report on small-angle neutron scattering measurements on the vortex lattice (VL) in the mixed state of CeCoIn$_5$ with the magnetic field ($H$) along $[100]$ and $[110]$. For both field orientations a distorted hexagonal VL is observed, reflecting the penetration depth anisotropy of the screening current plane. With $H \parallel [100]$ the VL is oriented with Bragg reflections along the [001]-axis at all fields. For $H \parallel [110]$ the same VL orientation is observed at low fields, followed by a $90^{\circ}$ first-order reorientation transition as $H$ is increased. We attribute this behavior to Fermi surface anisotropy coupled with non-local effects. For $H \parallel [100]$ we obtain the field dependence of the form factor ($|F|^2$) both within (50~mK) and outside (350~mK) the magnetic $Q$-phase. At both temperatures $|F|^2$ varies with $H$ in a manner similar to $H \parallel [001]$ [J.S. White {\em et al.}. New J. Phys. {\bf 12}, 023026 (2010)], due to the competition between Pauli paramagnetism and the antiparallel spin alignment of $d$-wave pairing giving rise to ``magnetized" VL cores.

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Authors

  • Morten Ring Eskildsen

    University of Notre Dame, IN, US, University of Notre Dame, IN, USA, University of Notre Dame

  • Pinaki Das

    University of Notre Dame, IN, US, University of Notre Dame, IN, USA, University of Notre Dame

  • A.T. Holmes

    University of Birmingham, UK

  • E.M. Forgan

    University of Birmingham, UK

  • A.D. Bianchi

    Universite de Montreal, Canada

  • J.S. White

    Paul Scherrer Institute, Switzerland

  • S. Gerber

    Paul Scherrer Institute, Switzerland

  • M. Kenzelmann

    Paul Scherrer Institute, Switzerland

  • J.L. Gavilano

    Paul Scherrer Institute, Switzerland

  • M. Zolliker

    Paul Scherrer Institute, Switzerland

  • C. Wang

    Los Alamos Natl. Lab., NM, USA

  • Eric Bauer

    Los Alamos Natl. Lab., NM, USA, Los Alamos National Lab, MPA-CMMS, Los Alamos Nat. Lab., MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM 87545, USA, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos, NM 87545

  • J. L. Sarrao

    Los Alamos Natl. Lab., NM, USA, Los Alamos Nat. Lab.

  • Cedomir Petrovic

    Brookhaven Natl. Lab., NY, USA, Brookhaven National Laboratory