Computing Barkhausen noise spectra for magnetostrictive thin film composites using efficient magnetization-magnitude preserving simulation techniques

Abstract

Barkhausen noise is a type of magnetic noise that occurs due to the interaction of domain walls with defects. In magnetic sensor applications, this can be a detrimental phenomenon since it disturbs the signal. We study this noise using coupled micro-magneto-mechanical finite element simulations. To this end, we consider in the first step a thermodynamically consistent material model within the generalized standard material approach. In our material model, we include exchange, anisotropy, demagnetizing, Zeeman, and elastic energy. The coupling between mechanics and micro-magnetics is implemented via a magnetostrictive strain contribution. In the following step, we extend the material model to represent the full Landau–Lifschitz–Gilbert magnetization dynamics. For the model extension, we give a detailed exposition of the finite element implementation. In particular, we use a new modified leapfrog/Crank–Nicolson time integration scheme, which preserves the magnetization magnitude exactly. Furthermore, we showcase in detail the scheme for applying our material model to noise computation (based on ensemble averaging). Finally, we investigate various numerical examples based on the magnetostrictive material FeCoSiB to illustrate the different features of our approach.