Neutron scattering experiments and simulations near the magnetic percolation threshold of Fe_(x)Zn_(1-x)F_(2)

The low temperature excitations in the anisotropic antiferromagnetic Fe_(x)Zn_(1-x)F_(2) for x = 0.25 and 0.31, at and just above the magnetic percolation threshold concentration x_(p) = 0.25, were measured using inelastic neutron scattering. The excitations were simulated for x = 0.31 using a localized, classical excitation model, which accounts well for the energies and relative intensities of the excitations observed in the scattering experiments.