Bethe Approximation for Pure and Diluted Magnets as Averaging over Local Exchange Fields

Resumo

An interpretation of the Bethe approximation based on the method of averaging over local exchange fields taking into account the correlation of neighboring spins is proposed. Based on this interpretation, an approximate method of analysis of Ising magnetics with nonmagnetic dilution is constructed. In the approximation considered, percolation thresholds and dependences of the Curie temperature on the concentration of magnetic atoms for lattices with different coordination numbers are calculated.