fully funded phd position available

Modeling Ultrafast THz-Induced Magnetisation Dynamics for Next Generation Data Storage and Processing

Project Description:
Research Area: Since the pioneering work of Beaurepaire and co-workers in 1996 [1], the field of ultrafast spin dynamics has rapidly developed. The ability to use femtosecond laser pulses to not only quench magnetic order, but reverse [2] and control it has opened up new possibilities for magnetic data storage and information processing. More recently, with recent advances in experimental methodology and the need for low-power future information technologies, there has been huge interest in the area of using finely tuned laser pulses with frequencies of light in the terahertz regime.

The aim of this PhD will be to develop models of terahertz-induced spin dynamics based on a multi-scale approach. The successful candidate will use state-of-the-art density functional theory methods alongside atomistic spin dynamics [2] to simulate the dynamics of complex magnetic materials after excitation with a terahertz laser pulse. He/she will work alongside a postdoctoral researcher and a senior scientist at the Science and Technologies Facilities Council working on the EPSRC project, TERASWITCH, to support his/her research and will be supported by experimental measurements through collaborations with the Free University in Berlin.

We are seeking a highly motivated graduate in physics, engineering or mathematics with experience in programming and strong mathematical skills. Knowledge of condensed matter physics and/or magnetism and magnetic materials, as well as knowledge of methods in computational magnetism/condensed matter (e.g. density function theory, monte-carlo methods), is desirable but not essential.

Application deadline: 12 noon 1st July 2020
We strongly recommend you contact the lead academic, Thomas Ostler t.ostler@shu.ac.uk to discuss your application

Start date for studentship: Enrolment in September 2020

Interviews are scheduled for: week commencing 13th July 2020.

For information on how to apply please visit https://www.shu.ac.uk/research/degrees Your application should be emailed to meri-student@shu.ac.uk and cc in t.ostler@shu.ac.uk by the closing date of 1 July 2020.

Funding Notes

The PhD studentship provides tuition fees at UK/EU levels and a maintenance bursary at the UK Research Councils’ national minimum doctoral stipend rate (£15,285 for 2020/21). The scholarship is available for three years of full-time or five years of part-time study (paid at 50%)

Information on entry requirements can be found at View Website

References

[1] – Beaurepaire et al. Ultrafast Spin Dynamics in Ferromagnetic Nickel. Physical Review Letters, 76(22), 4250–4253 (1996). https://doi.org/10.1103/PhysRevLett.76.4250

[2] – Ostler et al. Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet. Nature Communications, 3, 666 (2012). https://doi.org/10.1038/ncomms1666

Current Research in magnetism (CRIM) 2019

This year sees the return of the CRIM series in a different format to previous years highlighting current ‘hot topics’ in the field of magnetism. This year the theme is recent advances in antiferromagnetism. The one day conference will be held at the new IOP building, which is less than a 5 minute walk from Kings Cross, which is a great opportunity to see the new home of the IOP and what it has to offer.

Due to support from the IOP Magnetism Group and the Collaborative Computational Project on Magnetism (CCP-Mag) the event is free to register for IOP members and just £25 for non-members. Lunch and refreshments will be provided and there will be a mix of invited and contributed talks along with posters during lunch. Registration is now open at this link and abstract submissions are being accepted (see link here).

There are three confirmed invited speakers from the UK and Europe covering both experimental and theoretical advances in the field. The three invited speakers are:

  • Chiara Cicarelli, University of Cambridge, UK
  • Tomas Jungwirth, Academy of Sciences of the Czech Republic, Czech Republic
  • Eduardo Tapia, Peter Grünberg Institute (PGI), Germany

For further information see the conference website at https://www.iopconferences.org/iop/frontend/reg/thome.csp?pageID=883588&eventID=1399

New paper on

It has been known for over two decades that it is possible to manipulate magnetic order using femtosecond laser pulses. Many groups have demonstrated that single laser pulses can demagnetise a magnet on the picosecond time-scale, with a subsequent recovery of the order proceeding as the sample cools. Such measurements are routinely made these days using a pump-probe setup and detecting a change in the magnetic order through the Kerr effect. However, the pump beam is often micrometres across, hence what is measured is a spatial average. Just how the magnetic structure changes on the nanometre length-scale has, until now, not been well understood.

In a recent article in Nature Communications, in collaboration with several groups across the world, we have recently demonstrated how these magnetic structures vary across the nano-metre to micrometre length-scale and from the femto-second to nano-second time-scale. We have found “evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism”.

This has been very well explained in this article on the University of Colorado Boulder’s website. The article is open access and hence free for anyone to download and read.