Pearce joined the CDT in September 2017, having previously completed an MSci in Physics at Queen's University Belfast.
In Semester 1 of 2017-18 Pearce completed a short exploratory research project at the University of Glasgow in Putting the squeeze on skyrmions, supervised by Dr Damien McGrouther. In Semester 2 of 2017-18, he conducted a practical research project at Queen's University Belfast supervised by Dr Fumin Huang, Heat transfer in 2D materials.
CDT PhD Project
BRINGING AB-INITIO DESIGN TO THE LAB: DESIGN OF NEW PLASMONIC MATERIALS
Dr Lorenzo Stella, Queen's University Belfast
Professor Robert Bowman, Queen's University Belfast
Professor John Marsh, University of Glasgow
HAMR (Heat Assisted Magnetic Recording) is a technique being developed to increase the amount of data that can be stored on a magnetic hard drive. This is vital due to the increasing huge demands on data storage servers, and the relative expense of solid-state drives at the current time. Seagate, a global leader in data storage solutions, has therefore partnered with the CDT PIADS to deliver this PhD project aimed at tackling one of the key issues faced in the development of HAMR assisted recording devices.
HAMR requires a Near Field Transducer (NFT) which acts as an antenna to focus the energy from a finely focused laser onto a precise region (of the order of nanometers) of the target material. It is necessary to focus the energy onto such a small surface as materials used in HAMR recording devices consist of materials with a very fine crystal structure. The fine crystals, called grains, that make up such a material must be magnetized in exact directions in order for them to be used in data storage. Therefore, we need to confine the energy to only the grains being operated upon or else we risk the loss of integrity in the information being stored.
The NFT is therefore required to be a material that can condense energy down to an incredibly small scale. One class of materials that may be used for this purpose are “plasmonic” materials that store energy as physical motion in their free electrons. Using these materials, it is possible to pass the energy from the laser into a plasmonic material, and then into a small region of the target. However, there are currently several issues with currently available plasmonic materials, most importantly their ability to function in the harsh environments of temperature and pressure found in a HAMR read-write head. Most current materials are not robust enough to function in these environments without damage, and so alternative options are being sought.
Both Seagate technology and the CDT PIADS are enthusiastic about using simulations on an atomic scale to gain insight into optical and plasmonic materials that have applications in HAMR devices and therefore begin to make predictions of their fitness for use in future devices. This requires the development of computational modelling skills, specifically in Time Dependent Density Functional Theory (TDDFT), in order to produce and interpret data based on predictive models for the behaviors of the material.
The models used make use of classical and quantum-mechanical equations for the motion and energy transfer of the small particles that make up the material: atoms and molecules. Going deeper, calculations, especially for plasmonic materials, will make use of calculations for electrons and nuclei. This allows us to make predictions on the functionality of a material based on its intrinsic properties even if experimental results are not able to be found. This project is therefore held in the Atomistic Simulation Centre (ASC) of the QUB school of Mathematics and Physics under the supervision of Dr. Lorenzo Stella.
While the project is simulation in nature, close links will be kept with the Centre for Nanostructured Media (CNM), also in QUB, with the help of secondary supervisor Prof. Robert Bowman. This is to both aid in obtaining a better understanding of the use of these materials in a real-world setting (therefore gaining insight into potential limitations in the material) and, as the PhD progresses, potentially allow for time to be spent in the lab fabricating and testing the materials that have been simulated. This is to help assist in keeping the project grounded in the real-world problems faced by HAMR plasmonic devices. Additional supervision related to the University of Glasgow side of the CDT is under Dr. Donald MacLaren, and industrial supervision from Seagate Technologies is given by Dr Aiden Goggin.