Numerical Modeling and Characterization of Micromachined Flexible Magnetostrictive Thin Film Actuator

In this paper, a finite element model with in-plane and out-of-plane displacement for large deformation of the magnetostrictive thin film actuator is developed, and NiFe magnetostrictive thin film structures are fabricated with the micromachined flexible substrate using SU8-2025 and SU8-2075 (Shell Chemical Corp.). For the numerical analysis of large deformation of the magnetostrictive thin film structure, a shell element is proposed. The element stiffness matrix and force matrix are calculated, and numerical analysis is performed from the shell model. And magnetic moment of the film is measured to characterize the magnetic properties of the NiFe film with the SU8 substrate using a vibrating sample magnetometer (VSM) and deflections of the actuator under the external magnetic field due to the magnetostriction is measured using optical method to characterize the magnetomechanical characteristics. Also, the numerical results of magnetostriction analysis from the developed finite element model are compared with experimental results. Maximum deflection is about 110 $\mu$m under 0.5 T for microdevice application.