Low-energy spin fluctuations are studied for the electron-doped Fe-based superconductor LaFeAs-O1-xFx by inelastic neutron scattering up to an energy transfer of ω = 15 meV using polycrystalline samples. Superconducting samples (x = 0.057, Tc = 25K and x = 0.082, Tc = 29 K) show a dynamical spin susceptibility χ"(ω) comparable to that of the parent samples. However, χ"(ω) almost vanishes in the x = 0.158 sample, in which the superconductivity is highly suppressed. These results are compatible with the theoretical suggestions that spin fluctuation plays an important role in superconductivity.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)