A three dimensional rate equation model for the dynamical sensing effect of magnetostrictive Galfenol

A three-dimensional computational model for the dynamical sensing response of Galfenol magnetostrictive devices based on the rate equations is developed. The sensing model calculates the fraction of magnetic moments oriented along each of the energetically preferred directions of the crystal as a function of time, which can then be used to determine the time evolution of the total magnetization. Results from this 3D sensing model are compared to quasistatic loading experiments for the validation and extraction of phenomenological parameters. Using these extracted parameters, calculations are made for the dynamical sensing response. Thermodynamic effects are also incorporated into the model by a Boltzmann distribution of the magnetic moments in the crystal. Good quantitative agreement between the model and experiment at low magnetic bias fields and qualitative agreement at higher magnetic bias fields is obtained.