Photo of Dr Paul  Keatley

Dr Paul Keatley

Research Fellow

Email:

Telephone: 01392 724170

Extension: (Streatham) 4170

 

Research

I am a Post-Doctoral Research Fellow in the Electromagnetic and Acoustic Materials Group in the School of Physics and Astronomy. My primary research interests lie in the related themes of Spintronics and Magnonics for which I principally use time-resolved scanning Kerr microscopy (TRSKM)[1],[2],[3] to explore and understand high-frequency oscillatory processes of nanoscale Magnetic Materials on picosecond timescales. 

Since March 2017, I have been working on an EPSRC funded project on the 'optical detection of magnetisation dynamics induced by spin-orbit torques.' Specifically, I am using TRSKM to directly probe the sub-nanosecond motion of the magnetisation in nanoscale spin-orbit torque devices to understand the contribution of different torques resulting from fast current pulses passing through the device. Such devices are eagerly anticipated to underpin next-generation magnetic memory elements becasue of their potential for energy efficiency and design simplicity.  I am also constructing a new microscope to accommodate a 3D projected field electromagnet so that the spin-orbit torques acting within a variety of devices can be fully characterised and understood.  This new microscope will be compatible with an atomic force microscope (AFM) for near-field TRSKM that I developed in my previous post. 

Between December 2012 and September 2016 I worked on an EPSRC project to develop 'a plasmonic antenna for near-field magneto-optical imaging at the deep nanoscale.' Throughout this project I frequently engaged with AFM manufacturer Nanosurf and AFM probe manufacturer NanoWorld.  While the development of near-field tips with plasmonic antenna for deep-nanoscale magneto-imaging is ongoing, near-field TRSKM was successfully demonstrated using a sub-wavelength aperture.[4]  During this project I also combined the magneto-transport capabilities of the Spintronics theme with TRSKM to record nanosecond movies of the magnetisation dynamics generated by vortex spin-torque nano-oscillators[5] in collaboration with The Royal Institue of Technology (KTH), and the University of Gothenburg, in Sweden. This technique has since been applied to spin Hall nano-oscillators and will also be used in my current research on spin-orbit torque devices. An understanding of how the magnetisation dynamics of STNOs can be used to effectively couple multiple oscillators built on the same magnetic layers is anticipated to be the key to developing a new generation of nanoscale microwave oscillators for applications ranging from telecommunications to biosensing.  In May 2017, it was a pleasure to describe these experimental advances to Professor Alexander Halliday, FRS, Vice-President, The Royal Society, during his visit to the TRSKM lab.

From January 2008 to May 2012 I worked as a Post-Doctoral Research Associate supported by the EPSRC grant Spin@RT and the EU FP7 grant MASTER. During that time I implemented the magneto-optical measurement of phase-resolved ferromagnetic resonance spectra from individual nanomagnets,[6],[7] non-local spin transfer torque in an individual spin valve nano-pillar,[8] and coupled domain wall dynamics in pairs of magnetic nano-wires.[9] Immediately after my PhD I worked on the development of time-resolved x-ray photo-emission electron microscopy (TR-XPEEM) and x-ray ferromagnetic resonance (XFMR) measurements,[10] on the I06 Nanoscience beamline at the Diamond Light Source, Didcot, UK. These developments led to a new NSF-EPSRC grant with UC Berkeley for which XFMR is routinely used at Diamond and at the Advanced Light Source, Berkeley, USA.

I was awarded my PhD in 2008 for 'Time-resolved magneto-optical investigations of picosecond magnetisation dynamics in arrays of non-ellipsoidal ferromagnetic nano-elements.' During my PhD I constructed my first scanning laser microscope with integrated microwave probe station, and built two quadrant photodiode polarising bridge detectors for the vector-resolved detection of the static and dynamic magnetisation in scanning Kerr microscopes. This allowed in situ hysteresis loops to be acquired from microscale arrays of nanomagnets,[11] and the precessional trajectory of the magnetisation to be mapped.[12]

Since the start of my PhD I have worked on a number of collaborative projects with industrial partners HGST, Seagate, Crown Packaging, Unilever, and Llexan International. My work with HGST on arrays of nanomagnets led to the first spatial mapping of collective magnonic modes in arrays of nanomagnets,[13] while my work with Seagate led to the first mapping of flux beaming in hard disk writers.[14] During the project with Crown (June to November, 2012), I developed and successfully demonstrated a ferrite based radio frequency security tag for metallic retail packaging, which is now protected by a patent on which I am a named inventor.  This work led to an invitation to meet Greg Clark MP, UK Minister for Universities and Science, at the University of Exeter (October 14), and an invitation to present the work at an EPSRC IAA Showcase event (May 17). Subsequent research on similar prototypes for Unilever and Llexan International have been funded by two EPSRC Impact Acceleration Accounts for which I was appointed the post-doctoral researcher from September 2016 to February 2017, and from January 2018 to January 2019.

 

Education and Employment

  • 2013 -          Research Fellow, University of Exeter
  • 2008 - 2013 Associate Research Fellow, University of Exeter
  • 2004 - 2008 PhD Physics, University of Exeter
  • 1999 - 2003 MPhys Hons Physics, University of Exeter

 

Publications

I have authored or co-authored over 45 peer reviewed publications and have a h-index of 15 (Web of Science).

In 2016 I was selected as an Emerging Leader by the Editorial Board of Journal of Physics D and invited to publish my research in the 2017 Emerging Leaders Special Issue as part of the 50th anniversary of the Journal of Physics series.  See Keatley et al. Journal of Physics D: Applied Physics 50, 164003 (2017)

Patents

I have a patent for a 'Radio frequency detectable device' resulting from my work with Crown Technologies.

 

Conference Presentations

For a full list of my presentations, please click on conferences, seminars, and project meetings.

Invited talks and seminars presented by myself

  • 'Time-resolved scanning Kerr microscopy of magnetisation dynamics at the nanoscale' Colloquia and Research Seminars Series, December 2017, Cardiff University, UK 
  • 'High frequency magneto-optical measurements' R.J. Hicken and P.S. Keatley, Institute of Physics Postgraduate Magnetism Techniques Workshop, December 2014, University of York, UK
  • 'The magnetization dynamics of nano-contact spin-torque vortex oscillators' P.S. Keatley, Magnonics 2017, Magdalen College, Oxford, UK.
  • 'The magnetization dynamics of nano-contact spin-torque vortex oscillators' P.S. Keatley, 62nd Annual Magnetism and Magnetic Materials Conference, November 2014, Pittsburgh, PA, USA.
  • 'The magnetization dynamics of nano-contact spin-torque vortex oscillators'; P.S. Keatley, APS March Meeting 2016, New Orleans, Louisiana, USA.
  • 'Bottom up magnonics: Spin waves in isolated nanomagnets' P.S. Keatley, 2nd International Advanced School on Magnonics, June 2016, University of Exeter, UK.
  • 'Direct observation of magnetization dynamics generated by spin-torque vortex oscillators' P.S. Keatley, MOSAIC Workshop, June 2016, Kusthotell, Varberg, Sweden.
  • 'Magnetisation dynamics at the nanoscale' P.S. Keatley, CDT Bi-monthly meeting, November 2015, University of Exeter, UK.
  • 'Time-resolved scanning Kerr microscopy of magnetisation dynamics at the nanoscale' P.S. Keatley and R.J. Hicken, Condensed Matter Seminar Series, April 2015, University of Leeds, UK.
  • 'Time-resolved scanning Kerr microscopy of magnetisation dynamics at the nanoscale' P.S. Keatley and R.J. Hicken, Durham UK - India Workshop on Magnetisation Processes, March 2015, Durham University, UK.
  • 'Magnetisation dynamics at the nanoscale' P.S. Keatley and R.J. Hicken, Nanosurf Seminar, February 2015, Nanosurf, Liestal, Switzerland.
  • 'High frequency magneto-optical measurements' R.J. Hicken and P.S. Keatley, Institute of Physics Postgraduate Magnetism Techniques Workshop, December 2014, University of York, UK.
  • 'Time-resolved scanning Kerr microscopy of magnetisation dynamics at the nanoscale' P.S. Keatley and R.J. Hicken, Symposium on 'Frontiers of magnetisation dynamics at the nanoscale' at the 59th Annual Magnetism and Magnetic Materials Conference, November 2014, Honolulu, Hawaii, USA.
  • 'Time-resolved scanning Kerr microscopy: Application to Spintronic studies in Graphene' P.S. Keatley and R.J. Hicken, Quantum Systems and Nanomaterials Group Seminar, April 2012, University of Exeter, UK.
  • 'Dynamic dipolar coupling of edge modes in a pair of nanoscale ferromagnetic discs' P.S. Keatley, P. Gangmei, M. Dvornik, R.J. Hicken, J. Grollier and C. Ulysse, Spin Master Voice Workshop, December 2011, Chateau de Villiers-le-Mahieu, France.
  • 'Time resolved magneto-optical imaging of spin waves in magnonic meta-materials: Current status and novel opportunities' P.S. Keatley, P. Gangmei, M.K. Marcham, V.V. Kruglyak, A. Neudert, and R.J. Hicken, MAGNONICS kick-off meeting, September 2009, University of Exeter, UK.
  • 'Precessional magnetization dynamics in ultrathin magnetic nano-elements' P.S. Keatley, V.V. Kruglyak, A. Neudert, R.J. Hicken, J.R. Childress, and J.A. Katine, Third meeting of NEDO International joint research, September 2007, Wiesbaden, Germany.

Contributed talks and posters

I have also given 22 contributed talks in the USA, Europe, Asia, and the UK, in addition to 10 poster presentations in the USA, Europe, and the UK.

 

Contributions to the Community

  • I am an organising committee member of the forthcominng International Conference on Microwave Magnetics (ICMM), to be held in June 2018 at the University of Exeter, UK.
  • I am an organising committee member of the forthcominng international workshop on Emerging Applications of Spin Transfer Torque (EASTT), to be held in June 2018 at the University of Exeter, UK.
  • I was co-organiser and co-chair of the 'Early Career Researcher Symposium,' chair of the oral session on 'Spin Waves, Magnonics and Dynamics I,' and chair of 'Flash Poster Session II' at the 8th Joint European Magnetism Symposia (JEMS), August 2016, Glasgow, UK.
  • I was chair of the oral session on 'Graded Index Magnonics' at the 2nd International Advanced School on Magnonics, June 2016, University of Exeter, UK.
  • I was an assessor for one of the Best Student Presentation Awards at the 13th Joint MMM-Intermag Conference, January 2016, San Diego, California, USA.
  • I was a co-organiser of the international workshop on 'Optical polarisation conversion at the near field' hosted by the School of Physics and Astronomy, July 2015, University of Exeter, UK.
  • I was chair of the oral session on 'Magnonics' at the 59th Annual Magnetism and Magnetic Materials Conference, November 2014, Honolulu, Hawaii, USA.
  • I have reviewed manuscripts for Physical Review Letters, Physical Review B, Physical Review Applied, Applied Physics Letters, Advanced Electronic Materials, New Journal of Physics, IEEE Transaction on Magnetics, and Nature Publishing Group Asia Materials and Scientific Reports. Sine 2009 I have reviewed 19 manuscripts.

 

Outreach

  • 'Spintronics: A spin on electronics' A breakfast seminar to local business leaders at Final Friday Science, 29th September 2017, The Innovation Centre, University of Exeter, UK.
  • 'Spintronics: A spin on electronics' An informal seminar to the public at the Sidmouth Cafe Scientifique, 20th June 2017, Kennaway House, Sidmouth, UK. 
  • 'Smaller and faster: Magnets for data storage' Four short talks with experimental demonstration given to A-level students attending the Pre-University Physics Course (PUPC), July 2015, University of Exeter, UK.
  • 'Smaller and faster: Magnets for data storage' A seminar with experimental demonstration given to A-level students attending the Pre-University Physics Course (PUPC), July 2014, University of Exeter, UK.
  • 'Smaller and faster: Magnets for data storage' An informal seminar to the public at the Sidmouth Cafe Scientifique, Costa Coffee, May 2014, Sidmouth, UK.
  • 'From hard-disk to healthcare: What can spintronics do for you?' Public presentation by members of the Spin@RT consortium at The Royal Society Summer Science Exhibition 2008 by University of Leeds, Durham University, University of Warwick, University of Glasgow, and University of Exeter, June 2008, The Royal Society, London, UK.
  • 'Data storage and ultrafast magnetization dynamics in thin film magnetic materials' P.S. Keatley and R.J. Hicken, Public poster presentation at the British Association Festival of Science, September 2004, University of Exeter, UK

 

Memberships

I am a Member of the Institute of Physics and have online profiles with ResearchGate, Linked in, and Google Scholar. I am registered with ORCID.

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