Skyrmionics: From Magnetic Excitations to Functioning Low-Energy Devices

Lead Research Organisation: Durham University
Department Name: Physics

Abstract

Tony Skyrme proposed that under special circumstances it is possible to stabilize vortex-like whirls in fields to produce topologically stable objects. This idea, effectively of creating a new type of fundamental particle, has been realised with the recent discovery of skyrmions in magnetic materials. The confirmation of the existence of skyrmions in chiral magnets and of their self-organization into a skyrmion lattice has made skyrmion physics arguably the hottest topic in magnetism research at the moment. Skyrmions are excitations of matter whose occurrence and collective properties are mysterious, but which hold promise for advancing our basic understanding of matter and also for technological deployment as highly efficient memory elements. Following the discovery of skyrmions in a variety of materials, several urgent questions remain which are holding back the field: what are the general properties of the phase transitions that lead to the skyrmion lattice phase, the nature of its structure, excitations and stability and how might we exploit the unique magnetic properties of this matter in future devices? These questions have only recently begun to be addressed by several large international consortia and are far from being resolved. For the UK to contend in this highly competitive field a major project is required that brings together UK experts in materials synthesis and state-of-the-art theoretical and experimental techniques. We propose the first funded UK national programme to investigate skyrmions, skyrmion lattices and skyrmionic devices. Our systematic approach, combining experts from different fields is aimed at answering basic questions about the status of magnetic skyrmions and working with industrial partners to develop technological applications founded on this physics.

Planned Impact

{Knowledge impact: scientific}
Our research will generate immediate and significant cross-disciplinary impact that will benefit physicists, chemists and materials scientists studying magnetism, the wider community of many-body quantum mechanics and topological physics, and the areas of technological applications of magnetism and materials simulation. We are especially excited that this will impact across disciplines, enabling us to extend our research to those in the areas of materials discovery, thin film growth, topological physics and technological development.

{Knowledge impact: technical}
We will work towards the design of a skymionic device that will open up prospects for ultra-low power information and storage technologies. This will address the ever-increasing demands for processing and storing extraordinarily large amounts of data. Current spintronic devices work by reversing the magnetic ordering within micron-sized ferromagnetic domains. Skyrmions are of size 10 - 100 nm and are remarkably mobile. They can be created, transported and manipulated by electric and magnetic fields. Electrical current densities of 10^6 Am^-2 can cause skyrmion motion, which compares with 10^11 Am^-2 required to move ferromagnetic domains. Skyrmions therefore represent a potential route to high-density, low-energy magnetic storage and the smallest micromagnetic configuration objects for novel ultra low-power magnetoelectrical devices. We aim to develop skyrmionic materials towards the point of deployment in device applications in collaboration with our industrial partners. Also key to our proposal is the development and use of state-of-the-art measurement technologies and theoretical techniques. Working closely with industry we will align our scientific programme with the engineering and commercial realities of modern-day information technologies.

{Economic impact and IP}
The potential economic impact of skyrmionics is enormous. Ultra high density magnetic storage and low energy magnetic sensors could result from our research. IP generated in fields such as magnetic devices and information processing/computing will be identified and protected with the assistance of the knowledge transfer services from the institutions involved.

{People and training}
A project of this scale which involves significant staff time provides an opportunity to exploit a powerful and varied platform for training. This will centre around the cohort of PDRAs, who will be trained in a variety of state-of-the-art experimental and theoretical techniques including crystal and film growth, physical characterization and experimentation, theoretical modelling and industrial work. Each will benefit from the diverse range of techniques we will employ as part of the project and also from the range of working environments involved. Senior PDRAs will play a role in mentoring junior colleagues and supervising the work of PhD students. The PDRAs will manage and organise internal project meetings and seminars along with writing an electronic project newsletter and blog on the project website.

{Outreach}
Topological objects are not limited to skyrmions, but include domain walls (used in memory applications), vortices (used in superconducting devices) and monopoles (thought to exist in the early Universe). These are of increasing importance in modern science and technology but are relatively unexplored in the classroom, despite the fact that they are most easily explained with pictures rather than sophisticated mathematics. We will initiate an outreach effort as part of this project combining workshops for Key Stage 3 students along with an outreach website aimed at the established web-based community of popular science enthusiasts. Our outreach project aims to introduce the ideas of topological physics to a broad audience and stress its great potential for applications in future technologies.

Publications

10 25 50
 
Description In 1961 Tony Skyrme proposed that under special circumstances it is possible to stabilize vortex-like whirls in fields to produce topologically stable objects. This idea, effectively of creating a new type of fundamental particle, has been realised with the recent discovery of skyrmions in magnetic materials. The confirmation of the existence of skyrmions in chiral magnets and of their self-organization into a skyrmion lattice has made skyrmion physics arguably the hottest topic in magnetism research at the moment. Skyrmions are excitations of matter whose occurrence and collective properties are mysterious, but which hold promise for advancing our basic understanding of matter and also for technological deployment as highly efficient memory elements. Previously the UK had only a very small research footprint in this field and only a handful of researchers. We proposed the first integrated UK national programme to investigate skyrmions, skyrmion lattices and skyrmionic devices. As a result of the 6.5 year funded EPSRC Programme grant, uniting researchers from Durham, Warwick, Cambridge, Oxford and Southampton universities, the UK is now a major contributor in this field. We have overtaken France, the USA and China, and are competing with Germany and Japan.
Impact
{Knowledge impact: scientific}
Our research generated immediate and significant cross-disciplinary impact benefitting physicists, chemists and materials scientists studying magnetism, the wider community of many-body quantum mechanics and topological physics, and the areas of technological applications of magnetism and materials simulation. We benefitted from the UK's strong international and national facilities in x-ray and neutron scattering and developed new techniques enabling us to directly observe nanosized magnetic skyrmions and their behaviour under electric and magnetic fields. We were the first to directly image the three-dimensional nature of magnetic skyrmions and observe skyrmion tubes, which are now being considered as a new method of transferring information. We demonstrated how the structure of a magnetic skyrmion changes close to the surface of a material and were able to measure dynamic changes in the microsecond regime. We were the first group in the world to grow controllably doped single crystals enabling us to change transition temperatures and alter the dynamics of skyrmion formation and destruction. We also demonstrated we could control the lifetime of metastable skyrmions, even at room temperature, and to determine the formation energy of skyrmion tubes.
{Knowledge impact: technical}
We developed new ways of imaging skyrmions using electron microscopy and applied this to observing the behaviour of skyrmions in model devices, and have applied for a patent for the design of a room temperature skyrmion injector. This has led to a step change in our understanding and enabled us to build the first skyrmionics devices and demonstrate their potential advantages over current technologies. We have also demonstrated the very low energy costs of driving skyrmions, 100,000 times smaller than that required to move a ferromagnetic domain wall in spintronic devices. This will contribute to prospects for ultra-low power information and storage technologies, and will address the ever-increasing demands for processing and storing extraordinarily large amounts of data. Current spintronic devices work by reversing the magnetic ordering within micron-sized ferromagnetic domains. Skyrmions are of size 3 - 100 nm and are remarkably mobile. Skyrmions therefore represent a potential route to high-density, low-energy magnetic storage and the smallest micromagnetic configuration objects for novel ultra-low power magnetoelectrical devices. Working with our Industrial Liaison Board members we helped develop skyrmionic materials and developed state-of-the-art measurement technologies and theoretical techniques. This helped align our scientific programme with the engineering and commercial realities of modern-day information technologies.
Exploitation Route {Economic impact and IP}
The long term potential economic impact of skyrmionics is enormous. Ultra-high density magnetic storage and low energy magnetic sensors could result from our research. Currently the world uses approximately 20% of all the electricity generated for the IT industry with enormous amount of energy spent reading and writing magnetic memory on hard disk drives. This use is growing unsustainably and is expected to reach 30% by 2030. It is vital that lower energy cost technologies are developed over the next decade. Our IP generated in fields such as magnetic devices and information processing/computing will be protected with the assistance of the knowledge transfer services from the institutions involved.

{People and training}
Our collaborative team published over 200 papers over the period of the grant and the UK now has scientific and technical knowledge on the growth of high quality single crystals and how to produce thin film materials and devices. We also pioneered new ways of working at a distance during Covid. A project of this scale which involved significant staff time provided an opportunity to exploit a powerful and varied platform for training. This centred around the cohort of PDRAs, who were trained in a variety of state-of-the-art experimental and theoretical techniques including crystal and film growth, physical characterization and experimentation, theoretical modelling and industrial work. Each benefitted from the diverse range of techniques we employed as part of the project and also from the range of working environments involved. Senior PDRAs played a role in mentoring junior colleagues and supervising the work of PhD students. Our postdocs have gone on to careers in industry and academia and our PhD students won numerous fellowships and prizes

Topological objects are not limited to skyrmions, but include domain walls (used in memory applications), vortices (used in superconducting devices) and monopoles (thought to exist in the early Universe). These are of increasing importance in modern science and technology but are relatively unexplored in the classroom, despite the fact that they are most easily explained with pictures rather than sophisticated mathematics. We initiated an outreach effort as part of this project combining workshops for Key Stage 3 students Our outreach project introduced the ideas of topological physics to a broad audience and stressed its great potential for applications in future technologies.
Sectors Digital/Communication/Information Technologies (including Software)

Electronics

Energy

 
Description Participation in Science Festival Durham for School children Participation in Celebrate Science festival for children and families Saturday Morning Science Lecture for Children and families
Sector Digital/Communication/Information Technologies (including Software),Education,Electronics,Energy
Impact Types Cultural

Societal

Economic

 
Title CCDC 1960981: Experimental Crystal Structure Determination 
Description Related Article: Robert C. Williams, Paul A. Goddard, John Singleton, Jamie L. Manson|2020|Phys. Rev. Research|2|013082|doi:10.1103/PhysRevResearch.2.013082 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc23tkgz&sid=DataCite
 
Title Research data supporting 'Confinement of Skyrmions in Nanoscale FeGe Device-like Structures' 
Description Research data supporting 'Confinement of Skyrmions in Nanoscale FeGe Device-like Structures'. Detailed information contained in the associated read me file 'Data_info.txt' 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
URL https://www.repository.cam.ac.uk/handle/1810/343099
 
Description JSPS Summer scholarship for PhD student Max Birch to undertake research in Japan 
Organisation RIKEN
Department Institute of Physical and Chemical Research (RIKEN)
Country Japan 
Sector Public 
PI Contribution PhD student Max Birch applied to JSPS and was awarded a Summer fellowship which covered return travel to Japan and living expenses for 10 weeks in 2018. During his time in Japan he undertook research on skyrmions which led to joint publications.
Collaborator Contribution Supervision of PhD student, cost of equipment and consumables used. Travel by RIKEN staff to UK for research meetings.
Impact Research papers written. Details supplied under outputs.
Start Year 2017
 
Description JSPS Summer scholarship for PhD student Sam Moody 
Organisation RIKEN
Country Japan 
Sector Public 
PI Contribution Student preparing research programme, producing samples to take to Japan. Joint research undertaken with RIKEN.
Collaborator Contribution Supervision of PhD student for 10 week period. Joint research undertaken with Durham.
Impact The visit in Summer 2020 was delayed because of Covid until 2021. The visit happened August 2022 - November 2022.
Start Year 2019
 
Title Stable and manipulable Bloch point 
Description Simulation, data analysis, and plotting scripts to reproduce results reported in M. Beg et al. Stable and manipulable Bloch point. Scientific Reports 9, 7959 (2019).. 
Type Of Technology Software 
Year Produced 2020 
URL https://zenodo.org/record/2938932
 
Title Ubermag: Towards more effective micromagnetic workflows 
Description Supporting information for "Ubermag: Towards more effective micromagnetic workflows" 
Type Of Technology Software 
Year Produced 2021 
URL https://zenodo.org/record/4742523
 
Title Using Jupyter for reproducible scientific workflows 
Description Accompanying repository for "Using Jupyter for reproducible scientific workflows". 
Type Of Technology Software 
Year Produced 2020 
URL https://zenodo.org/record/4382224
 
Title ubermag/micromagnetictests: Universal micromagnetic tests for different calculators. 
Description Micromagnetic tests for Ubermag calculators 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
URL https://zenodo.org/record/3707737
 
Title ubermag/micromagnetictests: Universal micromagnetic tests for different calculators. 
Description Micromagnetic tests for Ubermag calculators 
Type Of Technology Software 
Year Produced 2020 
Open Source License? Yes  
URL https://zenodo.org/record/3707736