FOURTH ORDER PERTURBED HEISENBERG HAMILTONIAN WITH SEVEN MAGNETIC PARAMETERS OF BCC STRUCTURED FERROMAGNETIC ULTRATHIN FILMS-PART 1
Bcc structured ferromagnetic ultrathin films with two spin layers was described using fourth order perturbed Heisenberg Hamiltonian with all seven magnetic energy parameters. Magnetic energy per unit spin was expressed in terms of spin exchange interaction, second order and fourth order anisotropy, in plane and out plane applied magnetic fields, demagnetization energy and stress induced anisotropy in two spin layers. 3D plot of total magnetic energy versus angle and stress induced anisotropy were plotted for the different values of second order and fourth order magnetic anisotropy constants. All other magnetic energy parameters were fixed at constant values. The order of magnetic energy was changed when the values of fourth order anisotropy constants of two spin layers are interchanged. In addition, the graphs of energy versus angle were plotted to find the magnetic easy and hard directions. The angle between magnetic easy and hard directions is 90 degrees in this case.