Date of Award

Fall 10-2017

Embargo Period

11-8-2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science and Engineering

Advisor(s)

Vincent Sokalski

Comments

Recent developments in the study of perpendicular magnetic thin films have revealed that chiral magnetic effects such as the Dzyaloshinskii-Moriya interaction (DMI) can have a large impact on technologically relevant properties including domain wall (DW) mobility. A common technique for measuring DMI in thin films is asymmetric bubble growth, which uses an in-plane field to manipulate the Dzyaloshinskii DW and change its mobility in the field-driven creep regime. While this technique has been applied to several different material systems in many published studies, there remain a large number of anomalous results. In this thesis, we evaluate in greater detail the properties of Dzyaloshinskii DWs that govern creep mobility using both analytic and micromagnetic methods, arriving at an effective elastic band model to describe the DW. This model is then applied to experimental results in Co/Ni multilayer systems and is shown to improve the quantitative fitting of DW velocity. Our work allows for improved measurements of DMI in perpendicular thin films and provides a basis for future work in investigating as-yet-unexplained results and poorly understood chiral magnetic effects.

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