Lorentz TEM imaging of stripe structures embedded in a soft magnetic matrix

TL;DR

This study uses Lorentz TEM to analyze magnetic stripe structures in NiFe/NiFeGa hybrids, revealing size-dependent magnetic domain behaviors and demonstrating the technique's effectiveness for micron-scale imaging.

Contribution

It provides new insights into size-dependent magnetic domain transitions in stripe structures using high-resolution Lorentz microscopy.

Findings

Transition from discrete domains to effective medium when reducing stripe size from 1000 nm to 200 nm

High angle domain walls form during magnetization reversal in larger stripes

Lorentz microscopy effectively images periodic stripe structures at micron scale

Abstract

N\'eel walls in soft magnetic NiFe/NiFeGa hybrid stripe structures surrounded by a NiFe film are investigated by high resolution Lorentz transmission electron microscopic imaging. An anti-parallel orientation of magnetization in 1000 nm wide neighboring unirradiated-irradiated stripes is observed by forming high angle domain walls during magnetization reversal. Upon downscaling the stripe structure size from 1000 nm to 200 nm a transition from a discrete domain pattern to an effective magnetic medium is observed for external magnetic field reversal. This transition is associated with vanishing ability of hosting high angle domain walls between adjacent stripes. The investigation also demonstrated the potentiality of Lorentz microscopy to image periodic stripe structures well under micron length-scale.