Influence of Structure Fluctuations on the Curie Temperature and Susceptibility of Amorphous Ferromagnets

Abstract

Abstract Within the stochastical lattice model of amorphous Heisenberg and Ising ferromagnets the influence is investigated of fluctuations of exchange integrals on the Curie temperature T c for different spin values and numbers of nearest neighbours using the constant coupling approximation and a high temperature expansion for the susceptibility χ. T C and χ are always reduced by the fluctuations of the exchange integrals within the Heisenberg model for any spin and within the Ising model for S = 1/2 (for S ≧ 1 the situation is more complicated). The structure fluctuations lead to two opposite effects: 1. weakening of magnetic long range order and 2. increase of magnetic clustering (short range order).