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Harnessing Quantum Materials to design Antiferromagnetic Topological Textures

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

Abstract

The computing ecosystem uses 10% of the global electricity and contributes to 2% emissions (at par with aviation). Left unchecked, this demand is expected to rise rapidly to 21% by 2030. Hence, for energy sustainability, it is critical to develop computing platforms with dense, fast yet energy-efficient information storage and processing. An emerging candidate that can address these needs is spintronic memory and logic, which harnesses whirling magnetic topological textures (TTs) as dynamic information bits. In the last decade significant progress was made in developing ferromagnetic (FM) TTs. However, their practical utility has been inhibited by susceptibility to stray magnetic fields, strong internal dipolar fields, slow speeds and sideway motion. To alleviate these issues, there has been a surge of interest in discovering antiferromagnetic (AFM) analogues, which are predicted to be robust, scalable, ultra-fast and energy-efficient.

We have recently made the pioneering demonstration of a family of AFM TTs at room temperature. To harness them practically, it is now crucial to develop targeted electrical control pathways. To this effect, HQ-AFM will build a novel quantum materials platform that affords exquisite all-electrical control of homochiral AFM TTs via emergent interfacial phenomena. First, I will design multiferroic heterostructures, containing an epitaxial AFM layer sandwiched between ferroelectric (FE) and heavy-metal (HM) layers, hosting symmetry-breaking interactions to stabilize homochiral TTs. Then, I will exploit FE switching to realize electric-field tuning of their chirality, size and stability. Lastly, I will harness current-based spin-orbit torques injected from the HM layer to trigger their nucleation and ultra-fast motion. HQ-AFM will thus enable non-volatile, reversible and scalable control of AFM TTs, pushing the knowledge frontiers of AFM topological spintronics and forging the path to energy-efficient "beyond-Moore" computing paradigm.
 
Description We discover how to create, image and manipulate real-space topological textures in hematite iron oxide, including flexible membranes that can be integrated with silicon technology. These have potential application in next-generation information technology, which are now being actively explored. Key discoveries were made concerning the mechanisms by which emergent magnetic monopoles associated with these textures are created.
Exploitation Route We are now approaching the point where real-world technological applications can be explored. this will require further funding from UKRI and/or industry or via venture capital.
Sectors Digital/Communication/Information Technologies (including Software)
 
Description A state-of-the-art optical floating-zone furnace for crystal growth at high pressures
Amount £893,916 (GBP)
Funding ID EP/R024278/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2018 
End 08/2020
 
Description Oxford-Paris collaboration 
Organisation Unité Mixte de Physique CNRS/Thales
Country France 
Sector Public 
PI Contribution We brought a new line of research into the partner institute
Collaborator Contribution This collaboration was set up in the framework of the Marie Curie (MCSA) programme. Throughout the duration of the programme, the MSCA Fellow paid frequent visits to Paris, being hosted by the institute, and was allowed access to the growth cluster. Various Fe2O3 samples on different substrates were grown and characterised.
Impact A body of research is being pursued to stabilise sidle-domain antiferromagnetic films through miscue substrate engineering. Relevant experiments are ongoing.
Start Year 2022
 
Description Singapore NUS 
Organisation National University of Singapore
Country Singapore 
Sector Academic/University 
PI Contribution Original idea of the project, X-ray imaging of topological textures and data analysis
Collaborator Contribution Sample growth and initial characterisation
Impact Several high-profile publications, including, most recently Jani, H., Harrison, J., Hooda, S. et al. Spatially reconfigurable antiferromagnetic states in topologically rich free-standing nanomembranes. Nat. Mater. (2024). https://doi.org/10.1038/s41563-024-01806-2 Tan, A.K.C., Jani, H., Högen, M. et al. Revealing emergent magnetic charge in an antiferromagnet with diamond quantum magnetometry. Nat. Mater. 23, 205-211 (2024). https://doi.org/10.1038/s41563-023-01737-4 Jack Harrison, Hariom Jani, Junxiong Hu, Manohar Lal, Jheng-Cyuan Lin, Horia Popescu, Jason Brown, Nicolas Jaouen, A. Ariando, and Paolo G. Radaelli Holographic imaging of antiferromagnetic domains with in-situ magnetic field, Optics Express Vol. 32, Issue 4, pp. 5885-5897 (2024)
Start Year 2019
 
Description University of Cambridge 
Organisation University of Cambridge
Department Cavendish Laboratory
Country United Kingdom 
Sector Academic/University 
PI Contribution Original idea of the project, X-ray imaging of topological textures, contribution to image analysis and interpretation
Collaborator Contribution N-V centre measurements of topological textures and data analysis
Impact Tan, A.K.C., Jani, H., Högen, M. et al. Revealing emergent magnetic charge in an antiferromagnet with diamond quantum magnetometry. Nat. Mater. 23, 205-211 (2024). https://doi.org/10.1038/s41563-023-01737-4
Start Year 2021
 
Description "Leading Lights" interview 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact "Leading Lights" interview, explaining the research in lay terms and suitable to a broad audience.
Year(s) Of Engagement Activity 2024
URL https://www.diamond.ac.uk/Home/News/Campaign/Leadinglight/Paolo_Radaelli.html
 
Description A public lecture - Rust to Riches, the future of green computing 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact This was a public lecture to illustrate results recently published in the journal Nature. The lecture was recorded and published in our YpuTube channel.
Year(s) Of Engagement Activity 2021