Date of Award

2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Graduate Group

Electrical & Systems Engineering

First Advisor

Mark G. Allen

Abstract

Microfabricated magnetic MEMS components such as permanent micromagnets and soft magnetic structures are key enablers in various lumped and distributed systems such as energy harvesters, magnetometers, biomagnetic filters, and electromagnetic micromotors. The unique functionalities of such systems often require designers to controllably scale the relevant dimensions of a device relative to the characteristic length of a targeted application. We demonstrate in this dissertation that the developed Microlamination Technology could create two-dimensional uniform- or dual- height monolithic metallic structures with additional deterministic structural and compositional complexities along thickness direction, suitable to facilely and flexibly fabricate both lumped and distributed magnetic MEMS systems at a designer's will. The utility of the Microlamination Technology is further validated through the realization of two exemplary systems based on this technology:

(i) A lumped system of laminated permanent micromagnets. Microfabricated permanent magnets possessing a multilayer structure enabled by the Microlamination Technology that preserves the high energy density of thinner magnetic films, while simultaneously reducing average residual stress of the films and achieving a significant thickness are presented. The key to retain the superior magnetic properties of thin films in thick laminations is the low interface roughness between the layers, which in turn improves the coercivity of the micromagnets.

(ii) A distributed system of a bi-stable vertical magnetic actuator with non-contact latching. The utilization of the Microlamination Technology translates the structural periodicity (multilayer) into magnetic-field-pattern periodicity, which in turn enables the bi-stability of the microsystem and leads to the defined latching behavior. The latching mechanism is solely based on the magneto-static interaction without the need of a mechanical stop. No external energy is needed in the latching positions. This vertical bi-stable actuator could have potential applications as valves in micro-fluidic controls, and as integral parts of micro-mirrors in optical applications.

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