Linear and rotational magnetic micromotors fabricated using silicon technology

Different types of sliding, rolling, or rotating micromotors with rare-earth-based permanent magnet rotors are presented. The magnets move synchronously with rotating or traveling magnetic fields generated by 25-μm-thick gold current lines on silicon substrates. The magnets are guided in channels or openings in the silicon itself or in additional glass layers. For magnets with a typical dimension of 1 mm, forces and torques of 150 μN and 100 nNm were achieved. Maximum velocities of 24 cm/s and 2000 r.p.m. have been measured. Magnetic clamping to the bottom confines the rotor to the system and allows motor operation at any tilt angle. The noncontact magnetic transmission of forces to drive a ferromagnetic fluid has been demonstrated