Large Dzyaloshinskii – Moriya Interaction and Perpendicular Magnetic Anisotropy Induced by Chemisorbed Species on Ferromagnets

OVERVIEW

Using real-space magnetic imaging technique, researchers from Georgetown University, University of California - Davis, and Lawrence Berkeley National Laboratory have discovered that the chemisorbed species such as oxygen or hydrogen on the surface of ferromagnetic films can induce significant DMI that is comparable to that induced by heavy metals, despite the low atomic number of oxygen or hydrogen. They demonstrate that the chemisorption of oxygen or hydrogen on the ferromagnetic surface allows the creation and stabilization of novel spin textures such as chiral domain walls and magnetic skyrmions from systems with achiral magnetic states, indicating that earth-abundant oxygen or hydrogen could potentially be used as an alternative means to replace those rare noble metals in device applications. They further demonstrate that the magnetic chirality (being left- or right-handed) can be reversibly controlled by the chemisorbed hydrogen. These results open up new possibilities of using chemisorption to design and tailor spin-orbitronics devices.

BACKGROUND

Chiral spin textures have excited huge interest in condensed matter and materials science since the recent observation of chiral domain walls and magnetic skyrmions. The unique spin texture with a fixed magnetic chirality in magnetic skyrmions leads to a host of fascinating phenomena due to the topologically protected quantum state and emergent electromagnetic field, offering great potential for novel concepts in low dissipation magnetic information storage, or skyrmionics. The most widely used mechanism to stabilize magnetic skyrmions is the Dzyaloshinskii–Moriya interaction (DMI), originating from the broken inversion symmetry of a system. To date, sufficiently large DMI has been found in a limited set of bulk materials with chiral lattice, or in magnetic thin films adjacent to heavy metals.

Benefit

• The invention is highly relevant to spintronic devices, which are expected to be more energy-efficient and faster than conventional semiconductor devices.
• The invention also demonstrates that earth-abundant oxygen or hydrogen could potentially be used as an alternative means to replace those rare noble metals in device applications.
• The research results also open up new possibilities of using chemisorption to design and tailor spin-orbitronics devices.

Market Application

• This invention could be applied to areas of magnetic storage, magnetic memory and logic devices, and sensors.
• Potential customers may include leading semiconductor companies

Publications

US App Filed US20220199310A1
G. Chen, A. Mascaraque, H.Y. Jia, B. Zimmermann, M. Robertson, R. Lo Conte, M. Hoffmann, M.A.G. Barrio, H.F. Ding, R. Wiesendanger, E. Michel, S. Blügel, A. Schmid, and Kai Liu, “Large Dzyaloshinskii–Moriya interaction induced by chemisorbed oxygen on a ferromagnet surface”,Science Advances,6, eaba4924 (2020).
G. Chen, M. Robertson, M. Hoffman, C. Ophus, A. L. F. Cauduro, R. Lo Conte, H. F. Ding, R. Wiesendanger, S. Blügel, A. K. Schmid, and Kai Liu, “Observation of hydrogen-induced Dzyaloshinskii-Moriya interaction and reversible switching of magnetic chirality”,Physical Review X,11, 021015 (2021).
Gong Chen, Colin Ophus, Alberto Quintana, Heeyoung Kwon, Changyeon Won, Haifeng Ding, Yizheng Wu, Andreas Schmid, Kai Liu, “Reversible writing/deleting of magnetic skyrmions through hydrogen adsorption/desorption“,Nature Communications,13, 1350 (2022).