Magnetic properties of cubo-octahedral Ising clusters Article uri icon

abstract

  • The magnetic properties of large Ising clusters with cubo-octahedral structures are studied. The Ising Hamiltonian is solved in the mean field approximation and the magnetization and the Curie temperature are calculated for clusters sizes up to 2057 atoms. It is found that the dependence of Tc with respect to the total number of atoms (N) follows a finite scaling behaviour δ = 1 - Tc(N)/Tc(∞) = aN-λ. We find that λ = 0.593 and a = 2.924, for the case in which the magnetic coupling constants between spins are independent of their location in the cluster. However, these quantities change considerably when the coupling constant between surface spins is assumed to be different from the rest. These results clearly show the particular behaviour of finite aggregates. We present also the magnetization profiles of the sites lying on the central plane of a cluster with 923 spins. © 1993.

publication date

  • 1993-01-01