Magnetic domain pattern in hierarchically twinned epitaxial Ni-Mn-Ga films

TL;DR

This study investigates how the complex twinned microstructure of epitaxial Ni-Mn-Ga films influences magnetic domain patterns, combining microscopy and micromagnetic analysis to understand the effects of twin boundaries and film thickness.

Contribution

It provides a detailed analysis of the impact of hierarchical twinning on magnetic domains in Ni-Mn-Ga films, integrating experimental microscopy with micromagnetic modeling.

Findings

Twin boundary orientation affects magnetic domain configuration.

Finite film thickness influences magnetic band domain formation.

Microstructure-magnetic domain correlation is established.

Abstract

Magnetic shape memory alloys exhibit a hierarchically twinned microstructure, which has been well examined in epitaxial Ni-Mn-Ga films. Here we analyze consequences of this twin within twins microstructure on the magnetic domain pattern. Atomic and magnetic force microscopy are used to probe the correlation between the martensitic microstructure and magnetic domains. We examine consequences of different twin boundary orientations with respect to the substrate normal as well as variant boundaries between differently aligned twinned laminates. A detailed micromagnetic analysis is given which describes the influence of the finite film thickness on the formation of magnetic band domains in these multiferroic materials.