In-plane N\'eel wall chirality and orientation of interfacial Dzyaloshinskii-Moriya vector in magnetic films

TL;DR

This study experimentally investigates the orientation of the interfacial Dzyaloshinskii-Moriya interaction (DMI) vector in magnetic films, revealing that the out-of-plane component is negligible in certain epitaxial interfaces, which influences chiral domain wall stabilization.

Contribution

The paper provides experimental verification of the DMI vector orientation in epitaxial magnetic films using spin reorientation transitions to distinguish vector components.

Findings

Out-of-plane DMI component is negligible in studied interfaces.

Chiral Néel walls are stabilized in out-of-plane regimes.

Achiral Néel walls occur in in-plane regimes.

Abstract

The interfacial Dzyaloshinskii-Moriya interaction (DMI) is of great interest as it can stabilize chiral spin structures in thin films. Experiments verifying the orientation of the interfacial DMI vector remain rare, in part due to the difficulty of separating vector components of DMI. In this study, Fe/Ni bilayers and Co/Ni multilayers were deposited epitaxially onto Cu(001) and Pt(111) substrates, respectively. By tailoring the effective anisotropy, spin reorientation transitions (SRTs) are employed to probe the orientation of the DMI vector by measuring the spin structure of domain walls on both sides of the SRTs. The interfacial DMI is found to be sufficiently strong to stabilize chiral N\'eel walls in the out-of-plane magnetized regimes, while achiral N\'eel walls are observed in the in-plane magnetized regimes. These findings experimentally confirm that the out-of-plane component of the DMI vector is insignificant in these fcc(001) and fcc(111) oriented interfaces, even in the presence of atomic steps.