Magnetic properties of thick sputter deposited SmCo films for MEMS-applications

Summary form only given. Recent micromotor work clearly shows magnetic actuators as a viable alternative to electrostatic ones. One proven principle is the variable reluctance (VR) drive scheme, where softmagnetic poles magnetized by energized coils, are exerting attractive forces on a soft magnetic rotor or traveler (Gatzen et al. (2000)). A further increase of forces may be achieved by appropriately integrating hard magnets into the moving part, allowing the use of forces in opposite directions. The requirements on the hard magnetic material are a great BH energy product, the capability to achieve film thicknesses in the 30 /spl mu/m to 50 /spl mu/m range, and a technique to pattern the deposited film. A promising choice of material is sputter deposited SmCo. The magnetic properties of SmCo films were investigated and it was found that increasing the thickness of the SmCo layer led to a more isotropic magnetic behavior, thus allowing for either an in plane or a perpendicular magnetization of the hard magnetic film.