Analytical and numerical calculations of the magnetic properties of a system of disordered spins in the Ising model

We consider a system of randomly distributed magnetic atoms and describe the exchange interaction in the Ising model with a hydrogen-like dependence of the exchange energy on distance. The density of states for such system  was calculated using an advanced numerical algorithm. Furthermore, the density of states was calculated analytically. We established that finding the density of states allows calculating the dependence of magnetic susceptibility of  the system on temperature and magnetic field.