Tunable N\'eel-Bloch magnetic twists in Fe3GeTe2 with van der Waals structure

TL;DR

This study demonstrates the ability to tune Ne9el- or Bloch-type magnetic twists in the 2D van der Waals magnet Fe3GeTe2 using external magnetic fields, revealing insights into magnetic textures relevant for spintronic applications.

Contribution

It provides experimental evidence and analysis showing how magnetic twists in Fe3GeTe2 can be controlled without relying solely on interfacial Dzyaloshinskii-Moriya interaction.

Findings

Magnetic twists can be tuned by external magnetic fields in Fe3GeTe2.

The orientation of the modulation wavevector q depends on the sample structure.

Aligned domain walls exhibit fan-like modulations consistent with computational models.

Abstract

The advent of ferromagnetism in two-dimensional (2D) van der Waals (vdW) magnets has stimulated high interest in exploring topological magnetic textures, such as skyrmions for use in future skyrmion-based spintronic devices. To engineer skyrmions in vdW magnets by transforming Bloch-type magnetic bubbles into N\'eel-type skyrmions, the heterostructure of heavy metal/vdW magnetic thin film has been made to induce interfacial Dzyaloshinskii-Moriya interaction (DMI). However, the unambiguous identification of the magnetic textures inherent to vdW magnets, e.g., whether the magnetic twists (skyrmions/domain walls) are N\'eel- or Bloch-type, is unclear. Here we demonstrate that the N\'eel- or Bloch-type magnetic twists can be tuned in the vdW magnet Fe3GeTe2 (FGT) with/without interfacial DMI. We use an in-plane magnetic field to align the modulation wavevector q of the magnetizations in order to distinguish the N\'eel- or Bloch-type magnetic twists. We observe that q is perpendicular to the in-plane field in the heterostructure (Pt/oxidized-FGT/FGT/oxidized-FGT), while q aligns at a rotated angle with respect to the field direction in the thin plate by thinning bulk FGT. We find that the aligned domain wall twists hold fan-like modulations, coinciding qualitatively with our computational results.