Integration of Thin-Film Galfenol with MEMS Cantilevers for Magnetic Actuation

In this paper, the thin films of Galfenol were integrated with MEMS cantilevers for magnetic actuation. First, to determine the parameters that would yield maximum magnetostriction, Galfenol films were sputtered onto glass substrates using Galfenol targets with 18.4 atomic percent Ga. The sputter power was varied between 60 to 100 W for a sputtering time from 30 to 60 minutes, with argon flow rate between 20 to 40 seem. Using a capacitance bridge, it was determined that the largest magnetostriction strain coefficient of 147 ppm for a sputter power of 80 W at 60 minutes with argon flow rate of 20 seem. The thicknesses of these films were measured using a surface profilometer to all be around 150 nm. The films had a preferred crystallographic orientation of (110) as expected because it is the close-packed orientation for this BCC material. The compositions of the films were measured using energy dispersive spectroscopy (EDS) to be 24% Ga.