Prototype microactuators driven by magnetostrictive thin films

Abstract

Si microcantilevers coated with giant magnetostrictive Sm-Fe or Tb-Fe thin films are fabricated and the deflection of the cantilevers is measured as a function of magnetic field. In the case of a microcantilever with the dimension 3.7 mm (length) x 1.0 mm (width) x 13 mu m (thickness), for example, a very large deflection of 52 mu m is achieved at 150 Oe from the first ascending magnetic field, by the coating of a Sm42.7Fe56.9B0.4 thin film with the thickness of 1.2 mu m. Total deflection doubles when a magnetic field of the same amplitude (150 Oe) is applied alternately in the length and the width directions. Relatively large deflections are also observed for Tb-Fe thin film based microcantilevers as well as other Sm-Fe based cantilevers. The level of deflection achieved in the present magnetostrictive microcantilevers is considered to be suitable for microdevices applications.