ABSTRACT
Understanding the role of magnetism in unconventional super-
conductors is important for elucidating a microscopic mechanism
of high-transition temperature (high-Tc) superconductivity. The Fe-based superconductors show rich phenomena related to the
magnetism, including the long-range antiferromagnetic order and
the associated spin waves in their parent nonsuperconducting
materials. The optimal superconductivity is obtained through
suppressing the antiferromagnetic order by doping charge carriers
or other methods, while strong spin fluctuations persist in the
superconducting samples. This chapter gives a brief review on
the evolution of the antiferromagnetic spin fluctuations with
doping studied by both elastic and inelastic neutron scattering
techniques.
