Abstract
Spin fluctuations in superconducting (, ) are studied using inelastic neutron scattering. Well-defined commensurate magnetic signals are observed at (, 0), which is consistent with the nesting vector of the Fermi surface. Antiferromagnetic (AFM) spin fluctuations in the normal state exhibit a three-dimensional character reminiscent of the AFM order in nondoped . A clear spin gap is observed in the superconducting phase forming a peak whose energy is significantly dispersed along the axis. The bandwidth of dispersion becomes larger with approaching the AFM ordered phase universally in all superconducting , indicating that the dispersive feature is attributed to three-dimensional AFM correlations. The results suggest a strong relationship between the magnetism and superconductivity.
- Received 19 June 2013
DOI:https://doi.org/10.1103/PhysRevLett.111.167002
© 2013 American Physical Society