Date of Award

5-17-2015

Document Type

Honors Thesis

Department

Physics

First Advisor

Lars English

Language

English

Abstract

This project investigated the dynamics of 2-d easy axis magnetic spin systems. In particular, I studied the formation of intrinsic localized modes (ILMs) which arise from nonlinear behavior that manifests primarily as energy localization in a lattice. The formation and behavior of these ILMs were studied by varying the macroscopic shape of the lattice, which manipulates the frequency at which all the spins precess about the easy axis in an eigenstate called the uniform mode. I observed the formation of ferromagnetic domains in an antiferromagnetic lattice and the breakup of a one-domain ferromagnetic lattice. In both the ferromagnetic and antiferromagnetic lattices I observed strong synchronization of spins at the edges of ferromagnetic domains but nowhere else in the lattice, which is an unexpected result.

I also attempted to create structures known as skyrmions from an ansatz in these lattices (without the uniform mode), and observed the formation of a structure that strongly resembles a skyrmion, with one key difference. The spins in the skyrmion-like structure I created precess, but the entire structure maintains its topological index.

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