title: Structure, magnetic order and excitations in the 245 family of Fe-based superconductors.
abstract: Elastic neutron scattering simultaneously probes both the crystal structure and magnetic order in a material. Inelastic neutron scattering measures phonons and magnetic excitations. Here, we review the average composition, crystal structure and magnetic order in the 245 family of Fe-based superconductors and in related insulating compounds from neutron diffraction works. A three-dimensional phase-diagram summarizes various structural, magnetic and electronic properties as a function of the sample composition. A high pressure phase diagram for the superconductor is also provided. Magnetic excitations and the theoretic Heisenberg Hamiltonian are provided for the superconductor. Issues for future works are discussed.
authors.affiliation: Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Bao