| We have
investigated the three-decade-old controversy about BCC iron spin
dynamics at high temperatures using a classical Heisenberg
ferromagnetic model. First the static properties are computed by Monte
Carlo methods, and then spin dynamics simulations are performed. The
dynamic structure factor, an observable
in neutron scattering experiments, can be derived from the measured
correlation functions. From the simulations we can
extract information resembling both 'constant-E' and
'constant-/vec{q}'scans. We find peaks in both kinds of scans, and some
are nonzero l\vec{q}l or energies. At Tc some 'constant -\vec{q}' scans
have a noticeable peak centered at zero energy and two symmetric peaks
at nonzero energies which we believe are spin-wave peaks. |
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