Magnetoelastic effects in doubly clamped electroplated CoFe micro-beam resonators
Margo Staruch, S. P. Bennett, B. R. Matis, J. W. Baldwin, K. Bussmann, Daniel B. Gopman, Yury Kabanov, June W. Lau, Robert D. Shull, E. Langlois, C. Arrington, J. R. Pillars, Peter Finkel
Magnetostrictive Co77Fe23 films were fabricated on silicon wafers and fully suspended to produce free-standing, doubly clamped, micro-beam resonators. A negative or positive shift in the resonant frequency was observed for magnetic fields applied parallel or perpendicular to the length of the beam, respectively. Remarkably, we see a linear shift in the resonant frequency with higher bias fields oriented perpendicular to the beams length. Such linearity arises from an unusually high shape and stress-induced anisotropy energy, which results from the thin film suspension. Additionally, magneto-optic indicator film imaging elucidates the distinction in the reversal processes along the easy and hard axes. Together, these results suggest that, through careful modification of the magnetic anisotropy energies, both the frequency shift and angular dependence can be tuned to produce highly magnetic field sensitive micro-beam resonators.