Magnetostriction of a Hard Ferromagnetic and Elastic Thin-Film Structure

Abstract

In this paper, the magnetostriction of a thin film ferromagnetic and elastic structure is investigated. The structure is composed of an elastic layer confined between two perfectly bonded thin ferromagnetic layers in a plane strain setting. The ferromagnetic layers are saturated insulators and their magnetization is assumed at every stage parallel to the relevant layer's axis (latent microstructure). The structure is studied within the theory of magneto-elastic interaction and focus is set on reducing the problem to a manageable one-dimensional form. This is accomplished employing the Euler—Bernoulli kinematics in conjunction with Maxwell equations. Once the model is stated, a system of coupled nonlinear integro-differential equations is obtained in the deformation components. Integral terms spring from the non-local character of the magnetic interaction. Some features of the solution are pointed out through an asymptotic analysis. The system is solved through the spectral method and a collocation technique, employing Gaussian quadrature at a second grid to assess the magnetic field and an iterative solver for nonlinear systems. Plots of the deformed configuration, of the internal action and of the layers's interaction are given. A parametric analysis brings out the role of some dimensionless quantities. Finally, solutions are compared with experimental results on Nickel magnetostriction.