Dr Richard F. L. Evans

Lecturer | Assistant Professor

Fully funded PhD studentship available from October 2016

Thursday 25 February, 2016

A fully funded (EU/UK) PhD studentship working in one of the following areas is available starting in October 2016. Please email me at richard.evans@york.ac.uk for more details and how to apply.

Atomistic spin dynamics simulations of next generation permanent magnets

Climate change has renewed interest in the development of new Neodymium-based permanent magnets due to their application in energy efficient wind power generation and electric cars. However current materials are only around 20% efficient due to our poor understanding of the magnetic reversal processes. The aim of this project is to develop an atomistic model of DyFeB and NdFeB permanent magnets to study the magnetic properties with the goal of doubling the energy efficiency of the material. This could potentially double the power output from a wind farm or the range of an electric vehicle, leading to a major reduction in our need for fossil fuels.

Atomistic simulation of composite magnetic oxide materials for cancer treatment

Magnetic oxides are the most common magnets, commonly found in rocks around the world. Due to their biocompatibility, magnetite nanoparticles are currently being explored for use as a potential treatment for cancer, where an applied magnetic field causes them to generate heat which kills cancer cells. However, current magnetite particles have low performance in the safe size range of 10-20nm. The aim of this project is to develop an atomistic spin model of magnetite and similar oxides with the aim of modelling composite materials with much better performance, accelerating the time to market for this potentially life saving treatment.

Macroatomistic spin models of advanced magnetic materials

Atomistic spin models are immensely useful in describing atomic scale properties such as defects, interfaces and exotic magnetic structures such as ferrimagnets and anti-ferromagnets where the magnetization varies from atom to atom. However the computational cost means that until now these advanced models could only be used to study small scale system of a few hundred thousand atoms. Recent advances in computer hardware and parallel programming now allow us to use these state-of-the-art models to study large scale magnetic behaviour at the full-device level for the first time. This new and exciting development has opened up a range of possibilities, from studying domain wall processes, reversal mechanisms and thermal effects to complex magnetic structures such as a magnetic vortex (right), where the atoms are too small to resolve. The aim of this project is to investigate the atomic scale properties of complex magnetic devices at lengthscales of greater than 100 nm using supercomputers. Such simulations would give unprecedented insight into the behaviour of magnetic materials and the relationships between atomic structure and device performance. Read more.

Reconciling quantum and classical magnetism

Sunday 3 May, 2015

In a new paper published in Physical Review B we have devised a simple phenomenological temperature rescaling which corrects for the quantum mechanical stiffness present in a real ferromagnet. For the first time this allows classical spin models to correctly represent the temperature dependent magnetization of ferromagnets in direct agreement with experimental measurement. Read more.

Review paper featured in JPCM highlights of 2014

Monday 16 February, 2015

I am pleased to announce that my paper reviewing atomistic spin models and describing the methods implemented in the VAMPIRE software package has been selected as a highlighted article for 2014 in the Journal of Physics: Condensed Matter. Highlighted articles are selected based on referee endorsements, presentation of outstanding research and popularity and are free to read until the end of 2015. Read more.

Updates and upcoming research in 2015

Sunday 25 January 2015

With the arrival of the New Year I thought it would be a good time to talk about recent updates and my research plans for 2015. Last year was particularly neglectful of this site, but there are a lot of exciting developments upcoming and I will be blogging about these as they occur. Read more.

New paper on ultrafast switching in synthetic ferrimagnets published

Thursday 27 February, 2014

Schematic diagram of all-optical thermally induced magnetic switching

Our new paper published in Applied Physics Letters 104, 082410 (2014) has demonstrated a new possibility for all-optical switching synthetic ferrimagnet, a sandwich of two ferromagnetic materials and a non-magnetic spacer layer. The spacer layer engineers the coupling between the two ferromagnets so that they align opposite to one another. When subjected to an ultrafast laser pulse this structure spontaneously switches its magnetic state representing writing a single bit of data. Read more.