Superconducting Vortices in CeCoIn5: Toward the Pauli-Limiting Field
Andrea D. Bianchi,1*
Michel Kenzelmann,2,3
Lisa DeBeer-Schmitt,4
Jon S. White,5
Edward M. Forgan,5
Joel Mesot,3
Markus Zolliker,6
Joachim Kohlbrecher,3
Roman Movshovich,7
Eric. D. Bauer,7
John L. Sarrao,7
Zachary Fisk,1
Cedomir Petrovi
,8
Morten Ring Eskildsen4
Many superconducting materials allow the penetration of magnetic fields in a mixed state in which the superfluid is threaded by a regular lattice of Abrikosov vortices, each carrying one quantum of magnetic flux. The phenomenological Ginzburg-Landau theory, based on the concept of characteristic length scales, has generally provided a good description of the Abrikosov vortex lattice state. We conducted neutron-scattering measurements of the vortex lattice form factor in the heavy-fermion superconductor cerium-cobalt-indium (CeCoIn5) and found that this form factor increases with increasing field—opposite to the expectations within the Abrikosov-Ginzburg-Landau paradigm. We propose that the anomalous field dependence of the form factor arises from Pauli paramagnetic effects around the vortex cores and from the proximity of the superconducting state to a quantum critical point.
1 Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA.
2 Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland.
3 Laboratory for Neutron Scattering, ETH Zürich and Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
4 Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA.
5 School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK.
6 Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
7 MPA-10, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
8 Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
* Present address: Département de Physique, Université de Montréal, Montréal, Quebec H3C 3J7, Canada.
To whom correspondence should be addressed. E-mail: andrea.bianchi{at}umontreal.ca
