A novel actuation mechanism on the basis of ferromagnetic SMA thin films

Abstract A novel actuation mechanism is presented, which makes use of the antagonism of intrinsic magnetic and shape recovery forces acting on a ferromagnetic shape memory alloy (SMA) microactuator in a magnetic field. This mechanism is associated with large actuation and small biasing forces in each actuation direction resulting in a large stroke. Since no additional biasing elements are required, extremely compact designs are possible. As a demonstrator, an optical microscanner of 7 mm×3 mm×5 mm size is presented showing large scanning angles up to 120° in off-resonance mode. The scanning performance keeps frequency independent below a critical frequency, which is determined by heat transfer times.