EXPLANATION OF EASY AXIS ORIENTATION OF FERROMAGNETIC FILMS USING HEISENBERG HAMILTONIAN

摘要

For the first time, the easy axis orientation of some experimentally synthesized ferromagnetic thin films has been investigated using the second order perturbed Heisenberg Hamiltonian with stress induced anisotropy, demagnetization factor and fourth order anisotropy terms. The variation of average value of out of plane spin component with the temperature was plotted in order to explain the easy axis orientation. The temperature, at which the average value of out of plane of spin component becomes zero, was determined. The experimental values of temperatures corresponding to the in plane orientation of easy axis of ferromagnetic materials could be explained using our model. The deposition temperatures corresponding to in plane orientation of CoPt 3 films deposited on WSe 2 substrates and Fe-rich germanide films grown on Ge(001) substrates by some other researchers could be verified using this model. According to our model, the spin re-orientation temperature solely depends on the perpendicular component of internal magnetic field and the stress induced anisotropy.