Antiferromagnetic half-skyrmions and bimerons at room temperature

DOI: 10.1038/s41586-021-03219-6

Authors: Hariom Jani (National University of Singapore) , Jheng-Cyuan Lin (University of Oxford) , Jiahao Chen (University of Oxford) , Jack Harrison (University of Oxford) , Francesco Maccherozzi (Diamond Light Source) , Jonathon Schad (University of Wisconsin–Madison) , Saurav Prakash (National University of Singapore) , Chang-Beom Eom (University of Wisconsin-Madison) , A. Ariando (National University of Singapore) , Thirumalai Venkatesan (National University of Singapore) , Paolo G. Radaelli (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature , VOL 590 , PAGES 74 - 79

State: Published (Approved)
Published: February 2021
Diamond Proposal Number(s): 23857 , 20317

Abstract: In the quest for post-CMOS (complementary metal–oxide–semiconductor) technologies, driven by the need for improved efficiency and performance, topologically protected ferromagnetic ‘whirls’ such as skyrmions and their anti-particles have shown great promise as solitonic information carriers in racetrack memory-in-logic or neuromorphic devices. However, the presence of dipolar fields in ferromagnets, which restricts the formation of ultrasmall topological textures, and the deleterious skyrmion Hall effect, when skyrmions are driven by spin torques have thus far inhibited their practical implementation. Antiferromagnetic analogues, which are predicted to demonstrate relativistic dynamics, fast deflection-free motion and size scaling, have recently become the subject of intense focus, but they have yet to be experimentally demonstrated in natural antiferromagnetic systems. Here we realize a family of topological antiferromagnetic spin textures in α-Fe2O3—an Earth-abundant oxide insulator—capped with a platinum overlayer. By exploiting a first-order analogue of the Kibble–Zurek mechanism2, we stabilize exotic merons and antimerons (half-skyrmions)8 and their pairs (bimerons), which can be erased by magnetic fields and regenerated by temperature cycling. These structures have characteristic sizes of the order of 100 nanometres and can be chemically controlled via precise tuning of the exchange and anisotropy, with pathways through which further scaling may be achieved. Driven by current-based spin torques from the heavy-metal overlayer, some of these antiferromagnetic textures could emerge as prime candidates for low-energy antiferromagnetic spintronics at room temperature.

Journal Keywords: Ferromagnetism; Magnetic properties and materials; Phase transitions and critical phenomena; Spintronics; Surfaces, interfaces and thin films

Diamond Keywords: Antiferromagnetism; Spintronics; Skyrmions; Data Storage

Subject Areas: Materials, Physics, Information and Communication Technology


Instruments: I06-Nanoscience (XPEEM)

Added On: 05/02/2021 13:43

Discipline Tags:

Surfaces Quantum Materials Physics Electronics Components & Micro-systems Information & Communication Technologies Magnetism Materials Science interfaces and thin films

Technical Tags:

Microscopy Electron Microscopy (EM) PhotoEmmission Electron Microscopy (PEEM)