Scattering studies of emergent phenomena at extreme conditions of magnetic field and temperature.

Lead Research Organisation: University of Birmingham
Department Name: School of Physics and Astronomy

Abstract

This proposal asks for funding to construct a dilution refrigerator insert for the 17 T cryomagnet previously constructed with EPSRC funds (grant EP/G027161). This cryomagnet is currently being used at neutron scattering facilities throughout the European Economic Area, and is available for use by user groups unconnected with Birmingham, with any necessary support to be provided by us. With the dilution refrigerator insert, the cryomagnet will be able to cover a much larger range of desired experimental materials, without compromising the work that can already be done over the temperature range 2 K to 330 K. At present, this is the largest horizontal magnetic field available for use at any neutron scattering facility. Because small angle neutron scattering is of use to a large number of research communities, being able to move the cryomagnet around from facility to facility maximizes its utility, as it would not be in use full time at any one particular institution.

At present, this equipment has been used, amongst other things, to study the fundamental properties of cuprate superconductors and iron-based superconductors and the effects of magnetic fields on colloidal suspensions of fd virus. We propose to use it to look for anticipated single Landau level effects brought about by high fields in bismuth, as well as flux lines in Pauli-limited superconductors and non-centrosymmetric superconductors, and quantum magnetic ordering.

By extending the temperature range downwards by almost two orders of magnitude, we will be able to extend the research programme into a region where many emergent condensed matter phenomena occur. For instance, heavy fermion superconductors provide fascinating examples of unconventional superconducting phases arising from novel interactions. With the mK region accessible, the cryomagnet is well suited to the critical fields typical for these materials, so that most of their superconducting phase diagrams can be explored. This also makes it easier to investigate the effects of Pauli-limited superconductivity in heavy fermion and pnictide materials.

In addition, this grant will support use of all of the cryomagnet's capabilities by both ourselves and other user groups. As an example, some of our collaborators are very interested in using the cryomagnet to extend studies of magnetic alignment of mesoscopic structures in suspension. We will also be commissioning the cryomagnet at several other facilities, including synchrotron sources, with necessary adaptations to be driven by our collaborators.

Planned Impact

This project focuses on knowledge generation by pushing the experimental boundaries of what can be achieved in terms of combined magnetic fields and low temperatures at neutron and x-ray scattering facilities. This will be done by developing and commissioning a dilution refrigerator insert for a 17 T cryomagnet previously funded by EPSRC, lowering the base temperature accessible by nearly two orders of magnitude.

This new capability will be made available to other users through the proposal systems of the various large-scale facilities in the European Economic Area open to applications from UK users. This covers a range of scientific areas, from superconductivity, to magnetic devices, to studies of soft matter, such as viruses. Not all of these topics fall within our own scientific expertise, and so at the moment, we are not able to accurately assess the potential impact of these studies, but by involving as many other scientists we can, we maximize the value-for-money of this EPSRC-funded resource, and its likely impact on a broader scale.

To do this, we shall continue to publicise the cryomagnet and its capabilities to other scientists, by presenting the magnet and results obtained with it at suitable conferences. The facilities where it has been successfully commissioned, and may be used by other users, will be listed on our group website. This has a secondary benefit: by travelling to various large facilities in the European Economic Area, and presenting results obtained with this magnet, built by the UK company Cryogenic Ltd., we provide positive advertising for the company. To date, they have been contacted by two other groups interested in similar magnet systems.

As an example of potential impact outside our own area of scientific interest, one group has proposed a study of NdFeB magnets in high fields, to monitor changes in domain structure as a function of field. The aim of this work is to improve the functionality of the magnets at higher fields by assessing the role of composition and defects on the magnet quality. The results from this will filter through to manufacturers of NdFeB magnets very quickly. To show the breadth of possibilities, another idea that could be tested is that of using large magnetic fields to align mesoscopic materials to form photonic crystals.

Publications

10 25 50

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Lim J (2014) Coherent magnetic diffraction from the uranium M 4 edge in the multi-k magnet, USb in Journal of Physics: Conference Series

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Michels A (2020) Magnetic Guinier law. in IUCrJ

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Blackburn E (2013) Magnetism, superconductors, quantum systems in Neutron News

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Kindervater J (2015) Neutron spin echo spectroscopy under 17 T magnetic field at RESEDA in EPJ Web of Conferences

 
Description The main goal of this grant was to develop a dilution refrigeration system that could be fitted into the 17 T cryomagnet, constructed using a previous EPSRC grant, for use in X-ray and neutron scattering. This goal has been achieved. We have cooled to below 100 mK, and been able to maintain temperatures for a lengthy period of time. We are also able to remove the dilution refrigerator and replace with a standard VTI for experiments that do not require this. With this, X-ray and neutron scattering experiments can now for the first time be carried out at temperatures below 1.5 K in magnetic fields up to 17 T. This combination opens up new areas of investigation, particularly for unconventional superconductors. We have carried out a series of successful experiments on unconventional superconductors, and a large number of these have now been published, while some work is still being written up.

The dilution refrigerator is an unusual horizontal design, with an annular mixing chamber. The design and construction were all completed at Birmingham, using some techniques developed in collaboration with the jewellery industry in Birmingham.

The secondary goal of the grant was, during the development of this dilution refrigerator, to use the magnet in its previous configuration to carry out further experiments on the behaviour of a range of materials in extreme conditions of field and temperature. Most notably, we have discovered a new ordered state common to the high temperature superconductors using this magnet, and have been busy exploring this state. We have also found that previous theoretical ideas regarding the properties of superconductors at high fields appear to break down, from studies of the vortex lattice in some of these materials. These issues are still under exploration.
Exploitation Route We comnpleted a contract with the Helmholtz Zentrum Berlin to build a similar dilution refrigeration option for their own 26 T horizontal magnet for neutron scattering in 2019. We have collected data with this, as have other groups.

Our equipment has been used by other groups for experiments at the Institut Laue Langevin, including users from condensed matter physics, organic chemistry and protein crystallography.
Sectors Education,Energy,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology,Other

URL http://www.cm.ph.bham.ac.uk/publications/publications.html
 
Description As a result of the technical developments in this work, we completed contract with the Helmholtz Zentrum Berlin to use the expertise developed in dilution refrigeration in high magnetic fields to build a dilution refrigerator to operate at 26 T. This has been bult and delivered. Part of this expertise has involved collaboration with local Birmingham jewellery expertise, for manufacturing pieces from bespoke silver alloys.
First Year Of Impact 2019
Sector Other
Impact Types Economic

 
Description UK Neutron Strategy Panel
Geographic Reach Europe 
Policy Influence Type Participation in a advisory committee
 
Description EPSRC ISF 2016 - Developing Leaders
Amount £9,735 (GBP)
Funding ID EP/P511286/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 07/2016 
End 03/2017
 
Description Leverhulme Trust Emeritus Fellowship
Amount £21,830 (GBP)
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 12/2015 
End 11/2017
 
Title Holmes Bayes 
Description A new method of analysing data using Bayesian inference was implemented, to analyse small angle neutron scattering data. 
Type Of Material Data analysis technique 
Year Produced 2014 
Provided To Others? Yes  
Impact Since publication of the paper detailing this method, the software associated with it has been disseminated to a number of other research groups and research facilities, and it has been used to treat data in a number of subsequent publications and PhD theses. 
 
Description UoB HZB project to expand the available temperature range at the HZB High Field Magnet to temperatures below 0.5 K 
Organisation Helmholtz Association of German Research Centres
Department Helmholtz-Zentrum Berlin for Materials and Energy
Country Germany 
Sector Academic/University 
PI Contribution Our research team will be building a dilution refrigerator, using the expertise generated in EPSRC award EP/J016977/1, for use in the HZB High Field Magnet. We will then carry out some of the initial experiments with this unique combination of capabilities.
Collaborator Contribution Our partners are supplying some of the hardware, and will be installing the final result at their institute for general use by the research community.
Impact Not as yet.
Start Year 2016
 
Title Bayesian analysis add-on for the software GRASP 
Description An add-on to a pre-existing software package (GRASP) written by Charles Dewhurst. The add-no allows full Bayesian analysis of small angle neutron scattering data, providing better analysis of experimental results contained. The program is detailed in a publication, A. T. Holmes, Phys. Rev. B 90 024514 (2014). 
Type Of Technology Software 
Year Produced 2014 
Open Source License? Yes  
Impact The software has been adopted by several research teams around the world for this data analysis, and several publications have appeared using data treated by this program. 
 
Description EPS Res Conf 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Research conference held by University bringing together researchers from across all disciplines in the University.
Year(s) Of Engagement Activity 2014
 
Description Magnetism 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact National level conference; I was invited to provide an overview on magnetic vortices in superconductors.
Year(s) Of Engagement Activity 2015
 
Description Moreton Hall School 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact School visit.
Year(s) Of Engagement Activity 2014
 
Description OpenDays 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Open Days for the local community to visit the campus to find out about university activities. The audience is usually a mix of A-level students visiting universities and the local public. I have spoken about my area of research and provided multiple demonstrations.
Year(s) Of Engagement Activity 2008,2009,2010,2011,2012,2013,2014,2015
 
Description Pint of Science 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact This was an international festival, in a particular week, with science talks held in pubs at multiple locations around the world. For my talk, on our 17 T magnet and work done with this, there was an audience of around 30 people of a spread of ages and background interests. After the talk there was a lively discussion.
Year(s) Of Engagement Activity 2015
URL https://pintofscience.com/
 
Description RAL 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact 30 people attended seminar on research results.
Year(s) Of Engagement Activity 2015
 
Description RIXS UCL 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Meeting to establish interest in the UK for pursuing free-electron laser technologies and access.
Year(s) Of Engagement Activity 2014