Sputtering of SmCo Thin Films and Integration Into a Ferrofluidic Microactuator

The fabrication of SmCo films using physical vapor deposition (PVD), patterning by wet-chemical etching, and liftoff techniques as well as annealing processes was investigated. The composition of the film can be adjusted by the applied sputter parameters, i.e., the deposition pressure, the substrate bias voltage, and the power density by using a composite target. An intrinsic coercivity Hci of sputtered SmCo films above 0.8 MA/m and a maximal energy product |B XH|_max of above 70 kJ/m³ were achieved after an annealing process, respectively. A concept for the integration of sputtered SmCo permanent magnets in a ferrofluidic microactuator is presented. This microactuator consists of microcoil arrays which manipulate a ferrofluid plug in a microchannel. The permanent magnets provide holding positions for fixing the ferrofluid without power input.