Micromagnetic Modeling of the Magnetization Behavior of NiMnGa FMSMAs

TL;DR

This paper presents a micromagnetic model for NiMnGa ferromagnetic shape memory alloys, analyzing magnetization behavior considering twin microstructure effects and magnetostatic energy contributions.

Contribution

It introduces a new micromagnetic free energy model that incorporates magnetic anisotropy and magnetostatic energies for FMSMAs with twin variants.

Findings

Magnetization curves depend on twin variant volume fractions.

Magnetostatic energy significantly influences magnetization behavior.

Comparison shows the importance of including magnetostatic effects in models.

Abstract

The model calculations of the magnetization curves for the internally twinned NiMnGa ferromagnetic shape memory alloy are performed at the different volume fractions of twin variants. The method is based on the direct minimization of our new micromagnetic free energy model of FMSMAs taking into account both the magnetic anisotropy energy and the magnetostatic energy contributions associated with the laminated twin microstructure. The effect of the magnetostatic energy is discussed in comparison with some early models, where the magnetostatic energy was completely ignored.