FCC STRUCTURED FERROMAGNETIC FILMS WITH THREE SPIN LAYERS AS DESCRIBED BY FOURTH ORDER PERTURBED HEISENBERG HAMILTONIAN
Fourth order perturbed Heisenberg Hamiltonian was employed to determine the magnetic easy and hard directions of fcc structured ferromagnetic thin films with three spin layers. Only the spin exchange interaction, long range dipole interaction and second order magnetic anisotropy terms were taken into account. 3D graphs of total magnetic energy versus angle and spin exchange interaction were plotted for different values of second order magnetic anisotropy constants in three spin layers. In 3D plots, the peaks along the axis of angle are closely packed. However, some periodic variation of energy was observed along the axis of spin exchange interaction in 3D plots. The order of energy varies from 1014 to 1016 in these 3D plots. In addition, the graphs of energy versus angle were plotted in order to determine the magnetic easy and hard directions.