Ferromagnetic shape memory alloys show advantage relative to other smart materials for the construction of actuators. They allow for the construction of contact-less actuators because a magnetic field is used to drive the material and generate the output strain. The use of a magnetic field results in a faster response than in thermally driven shape memory alloys. On additional advantage is that when used in actuators, the device could conceivably be more reliable since it has fewer moving parts than an electro-mechanical or hydraulic actuator. We present the results obtained with a laboratory prototype of a ferromagnetic shape memory alloy-based actuator. A 12 mm long Ni–Mn–Ga single crystal is used as the active element, capable of producing a maximum stroke of 0.1 mm. We show that the position can be controlled with accuracies less than 20 nm RMS.
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