Active microcantilevers based on piezoresistive ferromagnetic thin films

We report the piezoresistivity in magnetic thin films of Fe0.7Ga0.3 and their use for fabricating self-transducing microcantilevers. The actuation occurs as a consequence of both the ferromagnetic and magnetostrictive properties of Fe0.7Ga0.3 thin films, while the deflection readout is achieved by exploiting the piezoresistivity of these films. This self-sensing self-actuating micromechanical system involves a very simple bilayer structure, which eliminates the need for the more complex piezoelectric stack that is commonly used in active cantilevers. Thus, it potentially opens opportunities for remotely actuated cantilever-based sensors. (c) 2011 American Institute of Physics. [doi:10.1063/1.3533390]