Antiferromagnetic order in CeCoIn5 oriented by spin-orbital coupling
Commissariat a l’Energie Atomique, UGA, INAC-FELIQS, 38000 Grenoble, France
Landau Institute for Theoretical Physics, 119334, Moscow, Russia
Received June 14, 2016
An incommensurate spin-density wave (Q phase) confined inside the superconducting state at high basal plane magnetic field is an unique property of the heavy-fermion metal CeCoIn5. The neutron scattering experiments and the theoretical studies point out that this state come out from the soft mode condensation of magnetic resonance excitations. We show that the fixation of direction of antiferromagnetic modulations by a magnetic field reported by Gerber et al., Nat. Phys. 10, 126 (2014), is explained by spin-orbit coupling. This result, obtained on the basis of quite general phenomenological arguments, is supported by the microscopic derivation of the χzz susceptibility dependence on the mutual orientation of the basal plane magnetic field and the direction of modulation of spin polarization in a multiband metal.
PACS: 74.70.Tx Heavy-fermion superconductors; PACS: 75.30.Gw Magnetic anisotropy; PACS: 71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn–Teller effect; PACS: 74.25.Ha Magnetic properties including vortex structures and related phenomena.
Key words: superconductor, heavy fermion, spin-density wave.