In this work the dynamics of permalloy circular magnetic islands of 225 nm radius and 10 nm thickness arranged into square lattices was investigated employing micromagnetic simulations.The simulations of the vortex magnetization loops and the ferromagnetic resonance (FMR) spectra were carried out using a free micromagnetics simulation software Mumax3. The obtained data was analyzed using Matlab. The simulations were carried out on a single vortex island as well as on two different lattices. The first lattice is comprised of interacting islands, while the second lattice - of non-interacting islands, separated by 25 nm and by 450 nm edge-to-edge distance, respectively. The magnetization loops were simulated by applying the static magnetic field in-plane of the single island or the lattice. The FMR simulations were carried out by applying the static magnetic field in-plane of the lattice and after the system reached the ground state in that field, the excitation as a sinc pulse was sent out along the out-of-plane direction of the lattice. The analysis of the obtained FMR spectra revealed that the several resonant modes are present for the single vortex island and the lattice, comprised of such islands. However, the physical explanation of the origin of those modes is a subject for further investigations.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-280767 |
| Date | January 2016 |
| Creators | Ciuciulkaite, Agne |
| Publisher | Uppsala universitet, Materialfysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | FYSAST ; FYSPROJ1055 |
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