Submitted on June 16, 2008
Accepted on August 7, 2008
Coupled Superconducting and Magnetic Order in CeCoIn5
M. Kenzelmann 1, Th. Strässle 2, C. Niedermayer 2, M. Sigrist 3, B. Padmanabhan 2, M. Zolliker 4, A. D. Bianchi 5, R. Movshovich 6, E. D. Bauer 6, J. L. Sarrao 6, J. D. Thompson 6
1 Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.; Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
2 Laboratory for Neutron Scattering, ETH Zurich & Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
3 Institut für Theoretische Physik, ETH Zurich, CH-8093 Zurich, Switzerland.
4 Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
5 Département de Physique et RQMP, Université de Montréal, Montréal, QC H3C 3J7, Canada.
6 Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Strong magnetic fluctuations can provide a coupling mechanism for electrons that leads to unconventional superconductivity. Magnetic order and superconductivity have been found to coexist in a number of magnetically mediated superconductors, but these order parameters generally compete. We report that close to the upper critical field, CeCoIn5 adopts a multicomponent ground state that simultaneously carries cooperating magnetic and superconducting order. Suppressing superconductivity in a first-order transition at the upper critical field leads to the simultaneous collapse of the magnetic order, showing that superconductivity is necessary for the magnetic order. A symmetry analysis of the coupling between the magnetic order and the superconducting gap function suggests a form of superconductivity that is associated with a nonvanishing momentum.
