Excitations in Heisenberg spin glasses. Pt. 2

For the Eusub(x)Sr1sub(-)sub(x)S-system in the spin glass regime (x = 0.6 and 0.4) the shape functions of the inelastic neutron scattering cross sections at low temperatures are calculated from a numerical study of the imaginary part chi (q.E) of the dynamic susceptibility at T = K. Within the calculation, the continued fraction algorithms of the preceding paper are applied. Additonally, for low temperatures, the spin-autocorrelation function PHIsub(l)sub(l) (t) = 0.5 x is calculated, averaged over all magnetic sites l. From this quantity, it is also derived, how the (metastable) Edwards-Anderson order parameter q(T) decreases with increasing T, namely proportional to (1 - const. x T2). Finally, from a numerical study of the inverse participation ratio it is concluded that the spin excitations in the upper half of the energy range covered by the density of states should be localized. (orig.)