Inelastic neutron scattering on iron-based superconductors

Ishikado, Motoyuki; Nagai, Yuki   ; Kodama, Katsuaki   ; Kajimoto, Ryoichi  ; Nakamura, Mitsutaka   ; Inamura, Yasuhiro; Mizuno, Fumio; Wakimoto, Shuichi  ; Nakamura, Hiroki  ; Machida, Masahiko  ; Suzuki, Katsuhiro*; Usui, Hidetomo*; Kuroki, Kazuhiko*; Iyo, Akira*; Eisaki, Hiroshi*; Arai, Masatoshi; Shamoto, Shinichi  

Three years have passed since the discovery of iron-based superconductors, its maximum superconducting transition temperature () is 55 K, resulting in second highest material system next to cuprate high- superconductors. Among various material systems in iron-based superconductors, we have systematically studied on LaFeAsOF (=28 K) of first discovered system and BaFe(As,P) which have recently attracted tremendous attention by the discovery of line nodes in its order parameter. In the session, we present recent results on "spin fluctuation and superconductivity on LaFePO", and "symmetry of order parameter on BaFe(As,P) by inelastic neutron scattering" studied by the chopper spectrometer 4SEASONS (J-PARC).