Giant Magnetostrictive, Spring Magnet Type Multilayers and Torsion Based Microactuators

There is a need for powerful active materials in microsystem actuators. Research on thin film magnetostrictive materials has concentrated on optimising the magnetostrictive response notably by reducing the required driving magnetic field. Here we present a novel type of multilayer, where 2 alloys having different properties are coupled together. The resulting composite system represents a new material with novel characteristics, which can not be fulfilled by simple alloys. In particular here we have investigated magnetostrictive multilayers, with remarkable low field performances (i.e. very large λ∂/∂H). Most magnetostrictive microactuators are based on a bimorph structure. However, these simple structures are prone to thermal drift. We present here also some results on a torsion based magnetostrictive microactuator prototype being insensitive to thermal drift.