EPSRC-SFI: Emergent Magnetism and Spin Interactions in Metallo-Molecular Interfaces

Lead Research Organisation: University of Leeds
Department Name: Physics and Astronomy


The interface between two materials can be used to give rise to new properties that neither component could have separately (emergence), to tune the capabilities found in of one of them (enhancement), or to share functionalities (proximity). Our range of magnetic materials is limited; only the metals iron, nickel and cobalt show spontaneous magnetic ordering at room temperature. Here, we use molecular interfaces to generate novel magnets outside the Stoner criterion, to control the spin properties of thin films and add functionalities. From a fundamental point of view, the origin of these effects is not fully explained due to the complexity of the interfaces, the materials involved and their intricate quantum-electronic properties. The scientific plan of the proposal is:

i. To develop a new theoretical framework to study magneto-molecular coupling and interfaces accounting for the many physical factors at play in the coupling between metals and molecules. These factors include, possibly in combination, interface structure and relaxation, the degree of re-hybridisation and the ensuing charge-transfer for the emergence and descriptors of interfacial magnetic ordering.

ii. To improve the properties of commonly used magnetic thin films via nanocarbon overlayers. Magnetic materials play a critical role in computing, sensors, power conversion and generation, signal transfer and many other technologies. Tuning of the desired properties is achieved via alloying between 3d ferromagnets and/or other metals (e.g. FeNi, FeCoB), by combining with rare earths (e.g. SmCo and NdFeB), using high spin orbit coupling interfaces (e.g. Co/Pt) or using oxides to achieve insulating ferrimagnets (e.g. YIG). These strategies can lead to a wide range of magnetic anisotropies, coercivities and conductivities. However, some functionalities, such as the electric control of magnetism, the combination of semiconducting and magnetic properties or enhancing the blocking temperature in magnetic elements remain elusive. Furthermore, some of the materials used in magnetism and spintronics are expensive, harmful to the environment and/or difficult to recycle. Molecular interfaces, on the other hand, make use of abundant, eco-friendly materials to bring about new or enhanced spin functionalities. Such opportunities include the generation of spin ordering in dia/paramagnetic metals, the control of coercivity (soften/harden), increases in the ordering temperature of nanostructures, the manipulation of the magnetisation axis, and improved performance in spin torque devices by tuning the spin orbit coupling.

iii. To create the opportunity for switchable magnetism by turning on/off the interfacial spin ordering using electric fields. Fully stable spin ordering is required in applications such as magnetic memories. However, having the capability to turn on and off the magnetic response of a sample would open new avenues of research and applications, from future high frequency superconducting electronics and qubits, to the design of sub-wavelength photo-memories. The properties of metallo-molecular interfaces are highly dependent on charge transfer and re-hybridisation. Electric or optical irradiation can therefore be used to control their magnetic response.

The consequences of spin ordering and polarised electron transfer are not limited to magnetic materials and their usage. Charge transfer is an essential chemical and biochemical process, and research in spin-related metallo-molecular coupling can also in the future contribute to other areas of science, such as electrochemical energy storage, electro-catalysis, and the use of metals in biomedical applications such as medical imaging.

Planned Impact

Our previous research demonstrated that the established premise that iron, cobalt and nickel are the only elements showing spontaneous magnetic ordering at room temperature can be beaten by using molecular interfaces. Although these three elements, plus their alloys, combinations and compounds fulfil a wide range of needs, the possibility of bringing a new class of magnets, with new functionalities and physico-chemical properties are the very exciting prospects that we bring here. However, our focus for the duration of the grant remains into basic research and understanding of this new phenomenon. The reach of this research has enormous potential, as demonstrated by the publication of the original results in a number of scientific dissemination magazines (Cosmos Magazine, Discovery Magazine), scientific websites (Physics Today, Nanowerc etc.) and blogs (IFL Science) that attracted tens of thousands of reads and thousands of comments from people all over the world.

From an economic point of view, there is a large number of companies in the UK, Ireland and elsewhere that depend on magnetic materials for computing (e.g. Seagate, Hitachi), in addition to small companies working on sensors, molecular electronics (e.g. Cambridge Display Technology), power conversion etc. It is estimated that 10% of the world's electricity in 2013 was used in ICT -with this number growing 3 times faster than the average electricity consumption between 2007 and 2012, although alternative strategies in data management have damped the most pessimistic predictions of the past. Approximately 80% is wasted in heat. Although our grant is focused in oriented basic research and fundamental understanding, this needs to be the first step towards new architectures where eco-friendly materials, low-power dissipation and versatility dominate technological goals.

The Irish-UK partnership represents an ideal complementary matching of capabilities that will maximise the benefits of resources from both countries towards an optimum output. Nanoscience and nanomaterials are essential to research in electronics, biophysics, polymer science and energy amongst others. The eventual impacts are far-reaching: for instance, the development of magnetic nanomaterials has allowed vast quantities of cheap data storage that underpin the internet and communications revolution, which has massively accelerated with ubiquitous mobile devices requiring access to cloud-based services (i.e. underpinned by magnetic memories and sensors).

From the point of view of outreach to the general public, magnetism and nanotechnology are fields that attract the imagination of students and people of all ages, particularly in terms of unusual emergent quantum phenomena and their applications to everyday appliances. In this regard, our research will provide examples of how fundamental, but application-motivated studies in many different areas can have impact on, and be impacted by, an advanced technology that is evermore present in most aspects of our lives. Opportunities for public engagement we can include outreach to schools (through Leads' 'Physics in Schools' module and TCD's Transition-Year Physics Experience, for instance), scientific workshops (e.g. Pint of Science) or council activities (e.g. Leeds Science Festival).

Another focus of the project is in career development and scientific transfer. The broad range, state-of-the-art physical and computational techniques involved, the close relationship between theory and experiments, and the novelty of the research will further increase the desirability of employment for the early career researchers hired throughout the project, while fostering the UK and Ireland's expertise in materials physics and technology.


10 25 50
Description 1.- Use of carbon-based molecules as a potential replacement for rare earths in permanent magnets -so far at low temperatures.
2.- Use of fullerenes to enhance the spin orbit coupling of heavy metals for spin-voltage conversion.
3.- Diffusion of spin triplets in metal-molecular interfaces.
4.- Molecular -induced changes in the magnetic and transport properties of metallic antiferromagnets (first evidence of this interaction)
5.- Temperature-dependent anisotropy changes in ultra-thin metals (<2 nm thick) with molecular interfaces.
6.- Discovery of a new method for magneto-optic information storage that allows ps information recording.
Exploitation Route Future strategies for rare-earth free permanent magnetism and spintronics devices (low-loss computing).
Increased speed and reduced power required to switch the magnetisation in magnetic, spin torque and heat-assisted memories using molecular interfaces.
Sectors Digital/Communication/Information Technologies (including Software),Electronics,Energy

URL https://magneticsmag.com/breakthrough-magnet-produced-from-thin-film-of-cobalt-and-carbon/
Description Report of results on Magnetics Magazine for their potential to change green energy generation (also reported in PhysOrg, EurekAlert! and Space Daily). Findings on picosecond molecular materials have also been reported by the ALBA Synchrotron: https://www.albasynchrotron.es/en/media/news/researchers-discover-a-new-mechanism-enabling-ultrafast-memory-architectures
First Year Of Impact 2020
Sector Energy,Environment
Impact Types Societal

Description Materials for low loss electronics (Roadmap)
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
URL https://www.royce.ac.uk/materials-for-the-energy-transition-low-loss-electronics/
Title Data on spin-singlet to triplet Cooper pair converter interface 
Description This dataset contains the measurements reported in the manuscript "Spin-singlet to triplet Cooper pair converter interface". In this study, we fuse magnetism and superconductivity in a system where spin-ordering and diffusion of Cooper pairs are achieved at a non-intrinsically magnetic nor superconducting Cu/C60 interface. Electron transport, magnetometry and low-energy muon spin rotation are used to probe time-reversal symmetry breaking in these structures. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
URL http://archive.researchdata.leeds.ac.uk/813/
Description ALBA PtMn 
Organisation ALBA Synchrotron
Country Spain 
Sector Academic/University 
PI Contribution Fabricated thin film multilayers of yttrium iron garnet and PtMn with or w/o molecular overlayers. Electron transport and magnetic characterisation.
Collaborator Contribution X-ray absorption spectroscopy and x-ray dichroism measurements, including staff time and free use of facilities.
Impact New beamtime access and in-kind support. Results contributing to research grants and publication in preparation. PR release by the facility and invitation to give a seminar.
Start Year 2022
Description Edinburgh TAS Co/C60/MnOx 
Organisation University of Edinburgh
Department School of Chemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution Fabricated and characterised spin photovoltaic devices. Sent PDRA to contribute to measurements.
Collaborator Contribution Time-resolved absorption spectroscopy, allowing the characterisation of our devices down to the sub-ps scale, which is the shortest ever investigated in magneto-molecular interfaces and spin photovoltaics.
Impact Publication and new lines of research.
Start Year 2019
Description ISIS - spin triplets 
Organisation ISIS Neutron Source Facility
Country United Kingdom 
Sector Learned Society 
PI Contribution Sample fabrication (superconducting - molecular - metal multilayers), data analysis.
Collaborator Contribution Facility access, expertise in polarised neutron reflectivity.
Impact Publication and general dissemination in scientific media.
Start Year 2020
Description PSI - low energy muon spin spectroscopy of muonium polaron and spin storage 
Organisation Paul Scherrer Institute
Country Switzerland 
Sector Academic/University 
PI Contribution Sample fabrication, experiments carried out at PSI in collaboration with local scientists and data analysis.
Collaborator Contribution Access to equipment, expertise on low energy muon spin spectroscopy, cryogenics and materials -across three beamtimes.
Impact Publications as included in the relevant section. New understanding of the interactions between muons and fullerenes.
Start Year 2019
Description Royce Institute sample growth 
Organisation Henry Royce Institute
Country United Kingdom 
Sector Academic/University 
PI Contribution Staff time and expertise in molecular thin film growth.
Collaborator Contribution Expertise in oxide and metal thin film growth.
Impact Collaboration in preparing the Low Loss Electronics roadmap together with the Henry Royce Institute and the IoP. Publications as per the relevant section.
Start Year 2020
Description TU Dortmund time resolved Co interfaces 
Organisation Technical University of Dortmund
Country Germany 
Sector Academic/University 
PI Contribution Thin film multilayers fabrication and characterisation (Co/C60; Co/Phthalocyanines; YIG/Pt, YIG/Pt/C60)
Collaborator Contribution Time resolved Kerr rotation measurements
Impact Initial measurements of the time-dependent magnetisation at the molecular interface.
Start Year 2022
Description Theory/DFT simulations 
Organisation Rutherford Appleton Laboratory
Department Scientific Computing Department
Country United Kingdom 
Sector Public 
PI Contribution Experimental results on magnetometry and spin-dependent transport.
Collaborator Contribution Collaboration with SCD for the computing modelling of magnetometry and transport results.
Impact Two publications (see list of outputs) in Physical Review B (2020) and ACS Applied Materials and Interfaces (2021).
Start Year 2019
Description Theory/DFT simulations 
Organisation Trinity College Dublin
Country Ireland 
Sector Academic/University 
PI Contribution Experimental results on magnetometry and spin-dependent transport.
Collaborator Contribution Collaboration with SCD for the computing modelling of magnetometry and transport results.
Impact Two publications (see list of outputs) in Physical Review B (2020) and ACS Applied Materials and Interfaces (2021).
Start Year 2019
Description Time resolved scanning Kerr microscopy 
Organisation University of Exeter
Department Exeter time resolved magnetism (EXTREMAG) facility
Country United Kingdom 
Sector Academic/University 
PI Contribution EXTREMAG facility at the University of Exeter
Collaborator Contribution Time-resolved scanning Kerr microscopy measurements down to the ps scale of hybrid magneto-molecular devices.
Impact These measurements allowed us to characterise the magneto-molecular interface, its anisotropy and potential applications in ultrafast memory storage.
Start Year 2020