Inducing Skyrmion Flop Transitions in Co$_8$Zn$_8$Mn$_4$ at Room Temperature

TL;DR

This paper demonstrates a controllable transition between in-plane and out-of-plane skyrmions in Co$_8$Zn$_8$Mn$_4$ at room temperature, using Lorentz microscopy and modeling, with potential applications in skyrmion-based devices.

Contribution

It introduces the first observation of a skyrmion flop transition at room temperature and shows how external field angle and film thickness control this transition.

Findings

Skyrmion flop transition occurs at room temperature.

Transition is controllable via external magnetic field angle.

Proposed a skyrmion-writing device based on this transition.

Abstract

Magnetic skyrmions are topologically-protected spin textures that manifest in certain non-centrosymmetric ferromagnets under the right conditions of temperature and field. In thin film skyrmion hosts, demagnetization effects combined with geometric confinement can result in two distinct types of spin textures: those with their axis of symmetry in the plane of the film (IP) and those with their axis pointing out-of-plane (OOP). Here we present Lorentz transmission electron microscopy evidence in conjunction with numerical modeling showing a flop transition between IP and OOP skyrmions in Co$_8$Zn$_8$Mn$_4$ at room temperature. We show that this skyrmion flop transition is controllable via the angle of the external field relative to the film normal and we illustrate how this transition depends on thickness. Finally, we propose a skyrmion-writing device that utilizes the details of this transition.