Reversible writing/deleting of magnetic skyrmions through hydrogen adsorption/desorption

Gong Chen,Colin Ophus,Kai Liu,Alberto Quintana,Andreas K Schmid,Changyeon Won,Yizheng Wu,Haifeng Ding,Heeyoung Kwon

doi:10.1038/s41467-022-28968-4

Abstract

Magnetic skyrmions are topologically nontrivial spin textures with envisioned applications in energy-efficient magnetic information storage. Toggling the presence of magnetic skyrmions via writing/deleting processes is essential for spintronics applications, which usually require the application of a magnetic field, a gate voltage or an electric current. Here we demonstrate the reversible field-free writing/deleting of skyrmions at room temperature, via hydrogen chemisorption/desorption on the surface of Ni and Co films. Supported by Monte-Carlo simulations, the skyrmion creation/annihilation is attributed to the hydrogen-induced magnetic anisotropy change on ferromagnetic surfaces. We also demonstrate the role of hydrogen and oxygen on magnetic anisotropy and skyrmion deletion on other magnetic surfaces. Our results open up new possibilities for designing skyrmionic and magneto-ionic devices.

Highlights

Magnetic skyrmions are topologically nontrivial spin textures with envisioned applications in energy-efficient magnetic information storage
One effective way to tailor magnetic domains is the control of magnetic anisotropy, especially near a spin reorientation transition (SRT), where domain patterns are very sensitive to small changes of magnetic anisotropy[38]
In our system of Ni/Co/Pd/W(110), the effective magnetic anisotropy can be tuned by adjusting the Ni layer thicknesses dNi and, as long as the Co layer thickness is in the range of a few monolayer (ML), two typical SRTs occur, similar to other systems with two SRTs39

Summary

Introduction

Magnetic skyrmions are topologically nontrivial spin textures with envisioned applications in energy-efficient magnetic information storage. We demonstrate the reversible field-free writing/deleting of skyrmions at room temperature, via hydrogen chemisorption/desorption on the surface of Ni and Co films. The DMI only occurs under conditions where inversion symmetry is broken, for example in bulk B20 compounds[5] or in thin films[6], and skyrmions have been observed experimentally in many of these systems[2,7] Due to their topologically protected spin configurations magnetic skyrmions have potential to be used as information carriers in spintronic applications, such as skyrmion-based memory[8,9], logic devices[10] or artificial neurons[11]. It was shown to prompt the formation of a magnetic skyrmion phase in the Fe/Ir(111) system in external magnetic fields at 4.2 K28 In these prior observations, the altered magnetic properties were attributed to absorption of hydrogen into the bulk of the materials. Multilayers changes the balance of magnetic energy contributions, the magnetic anisotropy, which in turn drives the skyrmion creation/annihilation as the energy landscape evolves

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Results

Conclusion