BCC STRUCTURED FERROMAGNETIC ULTRATHIN FILMS WITH TWO SPIN LAYERS AS DESCRIBED BY FOURTH ORDER PERTURBED HEISENBERG HAMILTONIAN. PART 1


Ferromagnetic films with bcc structure was investigated using fourth order perturbed Heisenberg Hamiltonian. Magnetic properties of ultrathin films with two spin layers were studied. Only spin exchange interaction, long range dipole interaction and second order magnetic anisotropy were taken into account. 3D plots of total magnetic energy versus angle and magnetic anisotropy constant of bottom spin layer were drawn for different values of magnetic anisotropy constant of top spin layer. When the magnetic anisotropy constant of top spin layer moderately increases, the total magnetic energy does not vary. On the other hand, when the magnetic anisotropy constant of top spin layer significantly increases, the total magnetic energy decreases. However, the gap between adjacent peaks does not vary with the increase of the magnetic anisotropy constant of top spin layer.