Dilute Ising ferromagnet: Its physical properties

Within the new type of correlated effective-field theory, which substantially improves the molecular-field approximation, we calculate the transition temperature, the critical concentration for site percolation, magnetization, correlated effective parameter, and initial susceptibility associated with the dilute ferromagnetic Ising system on a square lattice. The results are qualitatively satisfactory; the critical concentration $P_c$ is determined as $P_c=0.564\mathrm{}$. The effect, on initial susceptibility, of the (eventually) coexisting finite and infinite clusters is exhibited. It is shown that the correlated effective parameter exhibits some interesting behavior as a function of temperature for selected values of concentration of magnetic atoms.