Thermally controlled magnetization actuator (TCMA) using thermosensitive magnetic materials

A thermally controlled magnetization actuator (TCMA), that is actuated by changing the local magnetization of the structure by spot heating, is proposed and its feasibility is confirmed experimentally. The generated torque of this actuator is measured with a millimeter size torsional oscillator to confirm its feasibility. The torque variant achieved with thermally controlled magnetization is almost as large as that achieved with electromagnetization (current controlled magnetization). An integrated thermally controlled magnetization microrelay is fabricated to demonstrate the possibility of micrometer size actuating. The size of relay unit is 200/spl times/1500 /spl mu/m. Its armature beam is 10 /spl mu/m thick, 5 /spl mu/m wide, and 500 /spl mu/m long, and the tip is shaped like a hammer to increase the volume of magnetic material. The armature bending of 5 /spl mu/m has been achieved by attractive force between the stator and the hammer, enough for self-latching. Switching motion is created by 25 W/mm/sup 2/ of infrared laser beam irradiation. The contact force is calculated to be around 4 /spl mu/N.

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