EPSRC CDT in Metamaterials (PhD studentship): Detection of magnetic meta-atom dynamics by x-ray ferromagnetic resonance Ref: 2846

About the award

The studentship is part of the UK’s Centre of Doctoral Training in Metamaterials (XM2) based in the Departments of Physics and Engineering on the Streatham Campus in Exeter.  Its aim is to undertake world-leading research, while training scientists and engineers with the relevant research skills and knowledge, and professional attributes for industry and academia.

XM2 studentships are of value around £90,000, which includes £11,000 towards the research project (travel, consumables, equipment etc.), tuition fees, and an annual, tax-free stipend of approximately £14,500 per year for UK/EU students.

Exeter has a well-established and strong track record of relevant research, and prospective students can consider projects from a wide variety of fields:

  • Acoustic and Fluid-dynamical Metamaterials
  • Biological and Bio-inspired Metamaterials
  • Graphene and other 2D Materials, and related Devices
  • Magnonics, Spintronics and Magnetic Metamaterials
  • Microwave Metamaterials
  • Nanomaterials and Nanocomposites
  • Optical, Infra-red and THz Photonics and Plasmonics
  • Quantum Metamaterials
  • Wave Theory and Spatial Transformations

Please visit www.exeter.ac.uk/metamaterials to learn more about our centre and see the full list of projects that we have on offer this year.

International students are welcome to apply: fees and project costs will be paid, but the stipend can only be provided in exceptional circumstances.  We encourage international scholarship applicants or recipients to contact us directly prior to making their application (metamaterials@exeter.ac.uk).

Statement of Research

Joint supervisors: Prof Robert J Hicken, Prof Gino Hrkac

Industry partner: Seagate Technology

The interaction of microwave radiation with a magnetic multilayer is determined by the thickness and composition of its constituent layers. Since the layer thicknesses generally lie within the deep nanoscale range, and are much smaller than the microwave wavelength, the multilayer can be though of as a one-dimensional electromagnetic metamaterial. Each layer can be thought of as a meta-atom and full understanding of the dynamic behaviour of the metamaterial requires that the dynamic properties of each meta-atom be known and understood.  X-ray ferromagnetic resonance (XFMR) has a unique ability to determine the dynamical behaviour of meta-atoms of different composition because the photon energy of radiation generated by a synchrotron can be tuned to core level transitions that are element specific.

In this project the unique capabilities of XFMR will be used to study two highly topical problems.  Firstly, XFMR will be used to explore the spin wave excitations supported by magnetic exchange springs, which were first probed by ultrafast optical techniques in Exeter [1], in alignment with an EPSRC grant [2] that began in June 2017.  Secondly, the propagation of spin currents through antiferromagnetic layers will be studied.  Multilayer stacks will be studied in which two types of ferromagnetic layer with different magnetic resonance conditions are separated by antiferromagnetic layers.  When one ferromagnetic layer is at resonance, its precessing magnetization drives a spin current into the adjoining antiferromagnet through which it will propagate to the other ferromagnetic layer, inducing a dynamical response.  The technique is already well established having been demonstrated for the case of copper spacer layers [3], [4], as Exeter pioneered the development of phase-resolved XFMR at the Diamond and Advanced Light Sources.

Ultrafast and high frequency phenomena are of ever increasing importance in the development of information technology.  There are opportunities to apply underlying principles to new types of materials and devices, and to draw upon knowledge gained in other areas of science and technology. Therefore it is essential to remain aware of developments within neighbouring fields.  Membership of the CDT cohort and community will foster this awareness, while the skills training available within the CDT will provide a solid foundation for future employment.

[1] “Ultrafast optical parametric pumping of magnetization reorientation and precessional dynamics in DyFe2/YFe2 exchange springs”, L. R. Shelford, Y. Liu, U. Al-Jarah, P. A. J. de Groot, R. C. C. Ward, and R. J. Hicken, Phys. Rev. Lett. 113, 067601 (2014).
[2] “Picosecond Dynamics of Magnetic Exchange Springs”, EPSRC EP/P008550/1.
[3] “Phase-Resolved X-ray Ferromagnetic Resonance Measurements of Spin Pumping in Spin Valve Structures”, M. K. Marcham, L. R. Shelford, S. A. Cavill, P. S. Keatley, W. Yu, P. Shafer, A. Neudert, J. R. Childress, J. A. Katine, E. Arenholz, N. D. Telling, G. van der Laan, and R. J. Hicken Phys. Rev. B 87, 180403(R) (2013).
[4] “Direct detection of pure ac spin current by x-ray pump‐probe measurements”, J. Li, L. R. Shelford, P. Shafer, A. Tan, J. X. Deng, P. S. Keatley, C. Hwang, E. Arenholz, G. van der Laan, R. J. Hicken, and Z. Q. Qiu, Phys. Rev. Lett. 117, 076602 (2016).

About XM2

Metamaterials are fabricated microstructures having properties beyond those found in nature. They are an important new class of electromagnetic and acoustic materials with applications in many technology areas: energy storage and improved efficiency, imaging, communications, sensing and the much-hyped ‘cloaking’. Having recruited nearly 70 new PhD researchers in its first four years, the EPSRC Centre for Doctoral Training (XM2) hosted by the University of Exeter (www.exeter.ac.uk/metamaterials) will admit its fifth cohort of PhD students in September 2018.

The first year of the studentship includes an assessed, stand alone project, and a substantial programme of training. Students will choose from a wide range of taught modules, and participate in academic and personal development skills-based workshops, together with creativity events and conference-style meetings. The cohort will also be expected to disseminate their results to the international community via high-impact publications and international conferences. They will spend time working with our academic and industrial partners.  Full details of the programme are available here, or download a copy of our prospectus.

The University of Exeter combines world class research with excellent student satisfaction. It is a member of the Russell Group of leading research-intensive universities. Formed in 1955, the University has over 20,000 students from more than 130 different countries. Its success is built on a strong partnership with its students and a clear focus on high performance. Recent breakthroughs to come out of Exeter's research include the identification and treatment of new forms of diabetes and the creation of the world's most transparent, lightweight and flexible conductor of electricity. Exeter is ranked amongst the UK’s top 10 universities in the Higher Education league tables produced by the Times and the Sunday Times. It is also ranked amongst the world’s top 200 universities in the QS and Times Higher Education rankings.

Summary

Application deadline:31st January 2018
Number of awards:1
Value:Approximately £90,000, including research and travel budget, tuition fees and stipend (approximately [£14,500/£16,500] payable to UK or EU students only)
Duration of award:per year
Contact: Prof. Alastair Hibbins (Admissions Tutor)metamaterials@exeter.ac.uk

How to apply

Application criteria

During the application process you will need to upload the documents listed below. Please prepare these before starting the application process.

  • A statement describing why you would like to study for a PhD in Physics or Engineering,
  • A statement describing why you are considering a PhD programme that offers a cohort-based doctoral training model,
  • An academic CV,
  • A cover letter that discusses your preferred area(s) of study and/or your interest in a particular project/supervisor,
  • A document outlining your research interests and any relevant expertise,
  • Degree transcript(s) giving information about the qualification awarded, the modules taken during the study period, and the marks for each module taken,
  • The contact details of two academic referees.

Please note that of all the projects advertised we expect, as a Centre, to fill 15-20 posts only.

Shortlisting and interviews

Applications will be reviewed by members of the XM2 management board and candidates will be short-listed against a set of agreed criteria to ensure quality while maintaining diversity. Failure to include all the the elements above may result in rejection. Criteria will include:

ESSENTIAL

  • Excellence in a lower degree in a relevant discipline;
  • Excellence in written and oral skills in English;
  • Evidence of knowledge of XM2 ethos, research themes and/or supervisors.

DESIRABLE

  • Specialist knowledge about one or more XM2 topics;
  • Research outputs (e.g. papers) and/or has undertaken training in research methodology (e.g. undergraduate research projects);
  • Ability to work collaboratively

Short-listed candidates will be interviewed by a panel of two academic members of staff drawn from the management board. If successful, a second interview will be undertaken by the potential academic supervisors for the student concerned. Offers are normally made shortly after a successful second interview.