Tunable anisotropic magnetization damping in multiferroic structures

A great opportunity to study for a fully funded PhD while gaining valuable teaching experience.

6 years total duration, 0.5 FTE studying, 0.5 FTE teaching, compensated at currently £24983 p.a. pro-rata, therefore £12491
A student loan of up to £25000 in total over the six years may also be available to support this PhD (see Student Loans Company website for details).

Abstract
Research into fast magnetization dynamics [1] has seen a growing interest due to both the exciting physics involved and its application to spintronics devices, including magnetic memory devices and multiferroic tunnel junctions [2]. The ability to control and tune the magnetization switching processes is expected to result in a new generation of advanced spintronics devices and open a rich avenue of research. This project will investigate exactly this possibility, using a novel method for controlling magnetization precession damping in multiferroic devices.
Description
In magnetic materials damping of magnetization precession occurs due to energy transfer processes from the spin system to the lattice and it is an essential mechanism which determines the speed of magnetization switching in magnetic materials and spintronics devices [3]. Damping is commonly described using an isotropic scalar, α, the Gilbert damping parameter, within the Landau-Lifschitz-Gilbert description of magnetization dynamics. Theoretical investigations have shown that α is generally an anisotropic temperature-dependent tensor, supported by recent experimental evidence, although currently limited. In multiferroic structures, such as multiferroic tunnel junctions, by modifying the periodic lattice potential through voltage-dependent strain coupling [4] between a ferroelectric and ferromagnetic layer, the spin-orbit interaction which couples the spin to the lattice potential should result in a controllable modification of the anisotropy of magnetization damping.
You will study this theme using a number of techniques, including low-temperature ferromagnetic resonance (FMR), low-temperature time-resolved pump-probe MOKE, biaxial VSM with direct and inverse magneto-electric measurements capabilities, SEM, TEM, SPM techniques including AFM, MFM, PFM. The results obtained here will be analysed using a specially modified version of the micromagnetics software Boris, developed by Serban Lepadatu, to take into account the ellipticity of precessional orbits in order to reproduce the anisotropic FMR response.
This project involves external collaboration with Professor Marin Alexe, Warwick University, a world-leading expert on oxide thin films, including multiferroic tunnel junctions. A possible 3-month placement at the National Physical Laboratory will provide valuable experience and access to advanced measurement capabilities.

The Jeremiah Horrocks institute is based in Preston as part of the University of Central Lancashire. Preston has a proud history of manufacturing and production including the cotton mills of the 1800s and the production of aircraft in the early 1960s. Preston was granted City Status by Her Majesty Queen Elizabeth II in 2002.

Jeremiah Horrocks, from whom the institute gains its name, was an English astronomer. Born in Liverpool (1618 – 1641), he was the first person to demonstrate that the Moon orbits the Earth in an elliptical orbit. More notably, he predicted and was the only person to observe the transit of Venus of 1639.

The University of Central Lancashire has developed and evolved over time to become the fifth largest university in the UK. Founded in 1828 as the Institution for the Diffusion of Knowledge by Joseph Livesey’s Temperance Society. In 1886 the institute was expanded under the endowment of a local lawyer, Edmund Robert Harris (1804-1877). The institute was renamed to the Harris Institute and expanded to take on several new buildings. The institute was renamed in 1932 as the Harris Art College and in 1952 was renamed again to become the Harris College. In 1973, the College was renamed to become Preston Polytechnic and then later Lancashire Polytechnic in 1984. In 1992, the full university status was awarded and the University of Central Lancashire came into existence.

The Jeremiah Horrocks Institute was established in 1993 as the Centre for Astrophysics. Renamed in 2004 as the Jeremiah Horrocks Institute (JHI) for Astrophysics and Super-Computing, the JHI grew in 2012 to become the Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy. Already extremely well-regarded in astronomy and astrophysics research, the Institute has been investing in experimental physics since 2013 and now has a world-leading portfolio in nanophysics, magnetic materials and magnetic modelling, ionic liquids, strongly correlated electron systems and several other areas.