Fabrication of patterned magnetic microstructures using magnetically assembled nanoparticles

This work describes the modeling and experimental characterization of a fabrication method for forming magnetic microstructures using self-assembled iron oxide (Fe₃O₄) magnetic nanoparticles. This method can potentially be used in roll-to-roll production of magnetic structures patterned onto substrates or optionally lifted off to create free-floating micromagnetic actuators. This article reports: (1) the use of a selective magnetization process to create magnetic microstructures with complex, photolithographically defined shapes, (2) development of multi-physics simulations that model key fabrication steps (selective magnetization and particle assembly), and (3) experimental evaluation of the microstructure features (line width and height) as functions of process variables. The primary accomplishment is obtaining well-defined microstructures with complex shape and demonstrating their magnetic actuation when released as free-floating structures.