Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/142823
Title: SKYRMIONS AND MAGNONS IN MAGNETIC NANOSTRUCTURES
Authors: ZHANG LI
Keywords: magnetic nanostructure, spin wave, defect, Dzyaloshinskii-Moriya interaction, eigenmode, skyrmion
Issue Date: 2-Mar-2018
Citation: ZHANG LI (2018-03-02). SKYRMIONS AND MAGNONS IN MAGNETIC NANOSTRUCTURES. ScholarBank@NUS Repository.
Abstract: This thesis researches into the magnetic spin waves (SWs) and excitations in several types of magnetic nanostructures. Specifically, defect-induced properties of magnonic crystals, Dzyaloshinskii-Moriya interaction (DMI) of magnetic ultrathin multilayers, and eigenmodes of Néel skyrmions. The defect magnonic crystals studied are one dimensional periodic arrays of Ni80Fe20 stripes, with artificially-introduced periodic defect stripes. Their magnon dispersions, mapped by Brillouin light scattering (BLS), accord well with those calculated by finite-element analysis. Direct observations of the interfacial DMI was achieved using BLS. The nonreciprocal propagation of SWs induced by this interaction was measured in multilayer ferromagnetic films. Close agreement is found between the experimental data and the analytical calculations and demonstrates BLS as a viable probe for DMI. Micromagnetic modelling of the three fundamental eigenmodes of Néel skyrmions in ultrathin ferromagnetic films has been performed. Simulations reveal magnetic-field dependences of the modes in both skyrmion-lattice phase and in isolated-skyrmion phase.
URI: http://scholarbank.nus.edu.sg/handle/10635/142823
Appears in Collections:Ph.D Theses (Open)

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