This dissertation focuses on engineering advancements to solve technological challenges in the field of microrobotics. Like colonies of ants or bees, it is conceivable for coordinated "swarms" of small-scale robots to together solve complex tasks, such as micro/nanomanufacturing, biomedical treatments (e.g., direct cell manipulation, minimal invasive medicine, theranostics, etc.), monitor and maintenance of structures, or surveillance and information security. In the last few years, researchers have demonstrated significant advancements along this theme, including locomotion (magnetic, flaying, swimming), multiple robot manipulation, chemical actuation, and human in-vivo experimentation. This sci-fi idea has even been promoted in the general public by films like Fantastic Voyage (20th Century Fox -- 1966) and the recent Big Hero 6 (Walt Disney -- 2014). However, to fully realize this futuristic vision, the microrobot units must be made smaller, smarter, cheaper, and more capable than anything seen before.

To address some of these challenges, this research focuses on (1) the development of batch-fabrication strategies for scalable manufacturing of magnetic microrobots and (2) development of magnetic mechanisms to enhance the functionality of microscale robots. These efforts are unified by the micro-engineering of magnetic fields, structures, and devices at sub-millimeter dimensional scales.

In a first thrust, a batch-fabrication process denoted "selective magnetization" is developed to produce complex magnetic field patterns by "imprinting" permanent magnetic films/substrates with alternated microscale poles. Two examples illustrate the utility of the process for microrobotics: 1) a bottom-up approach, using magnetically driven assembly of magnetic nanoparticles for potential roll-to-roll manufacturing of freefloating microscale magnetic microrobots; and 2) a top-down approach, for mass production of diamagnetically levitated millimeter-scale robots to be used in high speed microfactories.

In a second thrust, two magnetic strategies are explored in an effort to enhance the functionality of microrobots (magnetic or non-magnetic robots): 1) magnetically attached end effectors, which are used to demonstrate nanoscale precision manipulation of micron size objects; and 2) sub-millimeter electropermanent magnets, which are magnet assemblies that can be used as electronically switchable magnetic actuators.

Ultimately, this research contributions are: a design a methodology, that can help future researcher in academia to continue building the field of magnetic microrobotics; a selective magnetization technology, that can be potentially used by industry to fabricate better and more functional magnetic devices at nano and micro scale; a novel magnetic force sensing technique at microscale, that can be used by researchers looking to enhance characterization capabilities in the microsystems field; a fabrication process for free floating magnetically responsive microstructures, that can potentially be used by researchers in biomedical applications; a fabrication technique for batch production of levitated microrobots with detachable end effectors, that can be used in new manufacturing and micropositioning technologies; and a proof of concept of the microfabrication of electropermanent magnets, that can be used to enhance functionally in the next generation of microrobots.