Monte Carlo modeling of bulk Gd

To understand the interplay between lattice structure and spin degrees of freedom, a bulk-Gd lattice as a hexagonal close-packed structure was generated and populated with paramagnetic Gd3+ ions with random projections (M-S(Gd)(i), i = 1, 245, or 443). Isotropic interactions of every site with their 12 nearest neighbors were taken into account. On the basis of the Monte Carlo Metropolis algorithm, the variation with temperature and magnetic field strength was obtained for the following physical quantities: magnetization M(T,H), the product of the magnetic susceptibility and temperature chi(mol)*T, magnetic specific heat C(T,H), entropy variation Delta S(T,Delta H), and statistics of spin projections M-S(Gd)(i,T). We also show the resulting interatomic exchange J(Gd)(-)(Gd), the reorientation of the spin temperature, the behavior of the Curie temperature versus a magnetic field, and magnetocaloric properties of bulk Gd.