Surface effect of magnetization of nanosized magnetic clusters

Based on the Monte Carlo method, magnetizations and spin-wave excitations at the surface, in the core for the clusters with different surface interaction, surface thickness and atom number are studied. It is found that, for the pure cluster, the Bloch T^3/2 law is well satisfied at low temperature (T<0.5T_C), B_s=3B_bulk and B increases drastically with the reducing atom number N; the magnetization and spin-wave excitations at the surfaces coated different exchange interaction are quite different from ones in the core. The simulated results are consistent with experimental facts, and are well discussed by the Bloch exponent law in the approximate crystalline approximation.