Microfabricated Electro-Permanent Magnets Using AlNiCo and CoPt

This letter demonstrates the fabrication and characterization of externally switchable electro-permanent magnets (EPMs) microfabricated on silicon wafers. Each EPM comprises a thick-film bilayer of electroplated cobalt-platinum as the hard magnetic phase and screen-printed aluminum-nickel-cobalt/polydimethylsiloxane composite as the soft magnetic phase. The selected magnetic materials and corresponding fabrication methods are compatible with standard semiconductor processes, which enable batch fabrication capability for low-cost and system-on-chip integration. An on/off magnetic moment ratio of 265 is achieved for the miniaturized 3.6 mm × 3.6 mm × 0.3 mm EPM devices by varying the volume ratio of the constituent materials. Scanning electron microscopy and vibrating sample magnetometry are used to characterize the microscopic structure and magnetic performance of the fabricated devices, respectively.