Electronic Theses and Dissertations

Trae Staggers

Date

2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Physics

Committee Chair

Shawn Pollard

Committee Member

Shawn D Pollard

Committee Member

Xiao Shen

Committee Member

Thang B Hoang

Committee Member

Daniel R Nascimento

Abstract

Since the discovery of gigantic magnetoresistance and the advent of spintronics, magnetic materials have become ubiquitous in modern technology. As such, a wide range of research areas within this field are being continuously explored for potential means to improve device scaling, decrease energy consumption, or increase speed, as well as to understand the fundamental physics governing spin order at the micro- and nanoscale. One of the avenues under current investigation involves the use of the spin-orbit interaction in systems with broken inversion symmetry through the introduction of interfaces or compositional variations. I will introduce the theory of micromagnetism and demonstrate my recent work utilizing computational micromagnetics to understand the influence of the spin-orbit interaction on domain wall dynamics and domain wall structure. First, the dynamics of domain wall velocities in Bloch and Néel type domain walls are explored without the influence of a Dzyaloshinskii-Moriya Interaction (DMI) with parameters that vary through the film thickness, such as saturation magnetization and exchange stiffness. These results are compared to the domain walls when a DMI is present. We find a shift in domain wall velocities that is similar in magnitude to those with DMI. Next, a mechanism for enhanced velocities without symmetry breaking in-plane fields are further examined to understand how these velocities scale with film thickness. The mechanism for this enhanced velocity is explored, as well as means to obtain further enhancements through controlled in-plane fields. Finally, the role of point-like topological structures known as domain wall skyrmions on kink skyrmion dynamics are detailed, including the emergence of a new, novel resonant mode.

Comments

Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Open Access

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