NMR Study of the FFLO State and Magnetism in CeCoIn5

We present 115In NMR results in a novel high magnetic field and low temperature phase of CeCoIn5 where exotic superconductivity coexists with the incommensurate spin-density wave order. The quantitative analysis for the field evolution of newly-emerged low-energy quasiparticle density of states is consistent with the nodal plane formation which is expected in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. The NMR spectra also suggest that the spatially uniform spin-density wave is induced in the FFLO phase.