Abstract
Micro devices, which are manufactured by micro fabrication process bases on the Micro-Electro-Mechanical-System (MEMS) technology, can be majorly classified as micro structure, micro sensors, and micro actuators. For the last group, numerous driving methods have been developed and the magnetic actuation is one of the most effective one. Recently, it again attracts people’s eye due to significant advantages that response rapidly, energy-saving and the great applicability in biochips. Though there many magnetic actuators have been proposed, but most of them were based on the magnetic properties in macroscale. In this thesis, micromagnetics is applied and two novel magnetic actuators are successfully demonstrated. One of our magnetic actuators is a suspended wave-shaped micro structure. Wet etching was used to fabricate the silicon dioxide suspended structure and magnetic thin films were deposited on it by E-gun evaporation. Owing to the strong magnetic shape anisotropy and the single-domain magnetization state of the magnetic films, expansion and contraction of the suspended structure can be actuated by applying field in different directions. Besides, under similar physical mechanism, magnetic micro tweezers made of two cantilever beams were also actuated successively. Tens of microns displacements of beams can be induced and the grab for a living cell was demonstrated.