A Numerical Investigation of Neel Wall Effects in Amorphous MI Ribbons

Abstract

We present new results from modeling the magnetoimpedance (MI) effect, which considers explicitly the experimentally observed stripe domain structure in MI ribbon elements. Specifically, we solve the Maxwell and the Landau-Lifshitz-Gilbert equations formulated in such a way that includes an <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">priori</i> known equilibrium magnetization. The equations are solved numerically for the real and imaginary parts of the magnetic field and magnetization simultaneously using a meshless method formulated in a point collocation scheme. Contrary to other models that have treated domain walls in a lumped parameter approach, we investigate the effects of the experimentally observed 180deg Neel walls directly. Additionally, resulting MIR values are computed and compared to published experimental data and the case ignoring domain structure for the amorphous ribbon. It is shown that the presence of the observed domain structure leads to greatly reduced MI voltages, and contributing mechanisms are discussed. Moreover, the results have a broader impact applying to other harmonic magnetic structures with and without 180deg Neel walls.