Studies of the magnetostriction in thin films: Experimental, analytical and numerical analysis

• The bending characteristic of a magneto-strictive thin film has been studied.
• An experimental setup is developed to evaluate the tip deflections.
• An analytical model is developed to predict the deflections by using theories of elasticity.
• A non-linear finite element model is used to simulate the behaviour of thin film.

Magnetostrictive thin films primarily find use for their actuation properties. Micro-electro-mechanical systems (MEMS devices) capitalize on the induced mechanical deformations when these thin films are subjected to a magnetic field. In this study, experiments are conducted on Tb–Dy–Fe thin film samples to determine their characteristic magnetization curves. The thin films are subjected to a periodically varying magnetic field of ±0.6 T and the deflections at the tip are measured. A simple analytical model based on the theories of elasticity and considering transversely isotropic material properties of both the film and the substrate layers has been proposed to predict the deflections. The study has been extended to predict the tip deflections numerically using Comsol Multiphysics. The measured tip deflections are further compared with the simulated analytical and numerical results, which are found to agree with each other.