CeCoIn5 ("Cerium-Cobalt-Indium 5") is a heavy-fermion superconductor with a layered crystal structure, with somewhat two-dimensional electronic transport properties. The critical temperature of 2.3 K is the highest among all of the Ce-based heavy-fermion superconductors.Detailed studies close to the critical field have been performed on CeCoIn5, and there is evidence that certain regimes in the phase diagram of this material should be interpreted in terms of the Fulde–Ferrell–Larkin–Ovchinnikov state.