Publications
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/13639
Browse
2 results
Search Results
Item Five Layered FCC Ferromagnetic Films as Described by Modified Second Order Perturbed Heisenberg Hamiltonian(University of Kelaniya, 2016) Samarasekara, P.; Warnakulasooriya, B.I.For the first time, the 2nd order perturbed Heisenberg Hamiltonian with all the seven magnetic energy parameters was solved for fcc structured ferromagnetic films with five layers. Previously, the 2nd order perturbed Heisenberg Hamiltonian was solved for four layered ferromagnetic films under some special assumptions by us. However, the exact solution of 2nd order perturbed Heisenberg Hamiltonian without any special assumption is formulated in this manuscript. The magnetic easy and hard directions were determined using the angles corresponding to the energy minimum and maximum in the 3-D and 2-D plots. The shape of the 3-D plots doesn’t change with the number of layers except the position of spikes. However, the magnetic easy direction varies with the number of layers. Most of the theoretical data obtained by our model agree with the experimental data of ferromagnetic thin films.Item Investigation of anisotropy constants dependence of ultra-thin ferromagnetic films with second order perturbed Heisenberg Hamiltonian(University of Kelaniya, 2007) Samarasekara, P.The variation of energy of ferromagnetic ultra-thin films with second and fourth order anisotropy was investigated using Heisenberg Hamiltonian with second order perturbation. The study was limited to sc(001) film with three layers. Graphs indicate energy minimums at certain values of second order anisotropy, fourth order anisotropy and angle. Films with fourth order anisotropy ω )4( Dm =4 can be easily oriented in the direction given by angle of 2.66 radians for the values of other energy terms used in this simulation. When the second order anisotropy ( ω )2( Dm ) is 3.1, preferred direction is 0.754 radians. When the second order anisotropy varies at a constant value of fourth order anisotropy, the graph indicates more energy minimums.