Mr Daniel Scobbie
|Postgraduate Student in the Department of Physics|
|Member of the Centre for Materials Physics|
I graduated from Durham University in 2022 with an integrated masters in physics and am now in the second year of my experimental PhD with Durham Superconductivity Group. As part of this I am also a member of the EPSRC Centre for Doctoral Training in the Science and Technology of Fusion Energy ( Home - Fusion CDT (fusion-cdt.ac.uk) ), following the materials strand.
The Fusion CDT
The first 6 months of my PhD were dedicated to the training provided by the Fusion CDT. Courses were delivered by 5 UK universities (York, Oxford, Manchester, Durham and Liverpool) with input from leading academics in the field and industry experts. They included fusion focused studies of plasma physics, plasma wall interactions, materials science and radiation damage.
My research focuses on the strain dependence of critical current density (Jc) in high temperature superconducting (HTS) materials. While the behaviour of these materials under 1-dimensional strain εx is relatively well known, in Durham an apparatus has been developed to perform Jc measurements under biaxial strains using a bespoke springboard sample holder. This is essential knowledge for the design optimisation of fusion magnet systems (eg for STEP: https://www.gov.uk/government/news/west-burton-selected-as-home-of-step-fusion-plant), which will be subject to large, multidimensional strains during operation. In addition to biaxial strains, the apparatus also allows Jc to be measured as a function of magnetic field strength (B), up to 15 T in our horizontal magnet system, and field-angle (θ).
- Measurement of Jc (B, θ) at 77 K and 0.3T, 0.5T and 0.7T for a SuperPower Advanced Pinning REBCO tape sample – see figure a) below. It was found that data from a previous sample where Jc had degraded showed agreement with the undegraded sample.
- Measurement of Jc (B, εx) at 77 K, fields of 0.3T, 0.5T and 0.7T, θ = 0o and -0.4% ≤ εx ≤ +0.3% - see figure b) below. The cycles were found to be reversible and displayed the expected inverse parabolic behaviour.
- Jc vs strain for repeated uniaxial strain cycles at T = 77 K, B = 0.5 T, θ = 0o - see figure c) below. The offsets in Jc seen between measurement cycles on different days are of interest as they may prevent the effect of any applied y-strain being distinguished. It is hoped they can be reduced by fixing the pressure, and hence the temperature at which the experiment is performed.
- 16th European Conference on Applied Superconductivity, 3rd – 7th September 2023, Bologna, Italy (Poster)
- Frontiers of Fusion student conference, 24th – 28th April 2023, York, UK (Poster)