Self-consistent approximation in the Ising model of pure and dilute magnets using a pair correlation

We construct a self-consistent approximation for calculating the magnetization and Curie temperature in the Ising model on an arbitrary lattice based on using the magnetization and pair correlation of nearest neighbors. We find the Curie temperatures for simple lattices in this approximation and generalize the approximation to the case of lattices diluted in lattice sites or bonds, for which we find the approximate values of the percolation thresholds.