Observation of Magnetic Skyrmion Bubbles in a van der Waals ferromagnet Fe3GeTe2

TL;DR

This study reports the direct observation of stable magnetic skyrmion bubbles in a 2D van der Waals ferromagnet, Fe3GeTe2, using Lorentz TEM, revealing their potential for spintronic applications.

Contribution

First direct observation of stable Bloch-type skyrmion bubbles in 2D vdW Fe3GeTe2, demonstrating their stability and formation under magnetic fields and temperature control.

Findings

Skyrmion bubbles form from magnetic stripe domains under external magnetic fields.

Hexagonal lattice of skyrmion bubbles achieved via field cooling.

Skyrmion lattices are stable against large tilt angles and confirmed by micromagnetic simulations.

Abstract

Two-dimensional (2D) van der Waals (vdW) magnetic materials have recently been introduced as a new horizon in materials science and enable the potential applications for next-generation spintronic devices. Here, in this communication, the observations of stable Bloch-type magnetic skyrmions in single crystals of 2D vdW Fe3GeTe2 (FGT) are reported by using in-situ Lorentz transmission electron microscopy (TEM). We find the ground-state magnetic stripe domains in FGT transform into skyrmion bubbles when an external magnetic field is applied perpendicularly to the (001) thin plate with temperatures below the Curie-temperature TC. Most interestingly, a hexagonal lattice of skyrmion bubbles is obtained via field cooling manipulation with magnetic field applied along the [001] direction. Owing to their topological stability, the skyrmion bubble lattices are stable to large field-cooling tilted angles and further reproduced by utilizing the micromagnetic simulations. These observations directly demonstrate that the 2D vdW FGT possesses a rich variety of topological spin textures, being of a great promise candidate for future applications in the field of spintronics.