Abstract
The excitation of the diluted Heisenberg antiferromagnet are studied using the coherent potential approximation (CPA) by extending the work of Harris et al. for the ferromagnet. The Green functions of the system are described in terms of an effective medium which is determined self-consistently using the CPA equation to treat the scattering of a vacancy and its neighbours. Results of calculations for the spectral weight function and for the density of states are presented. When compared with previous theories the present work is generally found to be more satisfactory. Comparison is also made with neutron scattering data for (Mn1-xZnx)F2 and excellent agreement is found.