Magnetic properties of Cobalt films described by second order perturbed   Heisenberg Hamiltonian
  Second order perturbed Heisenberg Hamiltonian was employed to investigate the magnetic properties of hexagonal Cobalt films. Initially the number of nearest neighbors and the constants arisen from the partial summation of the dipole interactions of the structure of cobalt were calculated using some special algorithms. Minimization of the energy difference between the easy and hard direction of a memory device is very important. When the energy difference between the easy and hard directions is significantly small, the magnetic moments in a memory device can be quickly rotated between easy and hard directions under the influence of a small magnetic field. The thickness of a cobalt film corresponding to this minimum energy difference calculated using this theoretical model agrees with some experimental data of cobalt based magnetic memory devices. 
P. Samarasekara and Amila D. Ariyaratne
cond-mat.mes-hall