Measuring magnetotransport properties of cuprate superconductors using high magnetic fields.
Lead Research Organisation:
University of Cambridge
Department Name: Physics
Abstract
For my PhD research I am researching high-temperature superconductors (HTSC) with a particular interest in their behaviour in high magnetic fields. I am looking at the cuprate family, with a chemical composition of the form of REBa2Cu3O6+x, where RE is a rare earth element, usually Yttrium (Y). Magnetotransport measurements are an excellent tool to understand the behaviour of these materials, but measurements need to be taken in the non-superconducting state. To achieve this I suppress superconductivity using magnetic fields. YBa2Cu3O6+x superconducting state is exceptionally resilient to applied field, so to perform these experiments I make use of high-magnetic field facilities.
People |
ORCID iD |
| Suchitra Sebastian (Primary Supervisor) | |
| Alexander Hickey (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/N509620/1 | 01/10/2016 | 30/09/2022 | |||
| 1948670 | Studentship | EP/N509620/1 | 01/10/2017 | 31/03/2021 | Alexander Hickey |
| Description | The achievements of my PhD so far are focused around two main areas. The first is development of electronics and data processing software to improve our experiments at high field facilities. The electronics such as tallied bandpass filters reduce the experimental noise allowing the same measurement to provide more insights into the properties of the superconductor. Streamlined data processing software then allows the experimental set up to be quickly adjusted and optimised to make the most of the set time slot that I have access to at these international facilities. The second area is using these techniques to perform magnetotransport studies exploring the phase diagram of the superconductor YBCO. The main result I want to high light is our current dependance studies looking at how field, temperature, current, induced disorder, and chemical doping all effect the onset of the zero resistive state. I find that these relations are highly non-linear indicating that simple models often use to describe the superconducting state in are not sufficient in the presence on high magnetic fields. Our finding indicate that the vortices inside the superconducting state must be interacting and these interactions change the macroscopic properties that we measure. |
| Exploitation Route | My research will be taken forward with the attempt to further understand the behaviour of this lower temperature, high magnetic field state of high temperature superconductors. From my results it is apparent that vortices play an important role in the the behaviour of these materials, it is also seen that interactions between the vortices are required to explain the macroscopic properties. More work can still be done though to develop a microscopic model of how these vortices are interacting. To do this trying to see this behaviour in other cuprate superconductors would be beneficial. It would also be advantageous to extend these measurements to lower temperatures. Also the software and electronics that I made to perform these experiments are now used by the rest of my group for a verity of measurement techniques, on a large array of materials. This will continue to happen after I have finished my PhD, and i hope and believe that they will be further developed after I have left. |
| Sectors | Electronics,Energy |
| Description | My research focuses on the low temperature high magnetic field properties of REBCO superconductors. While this environment is rare and difficult to reach, this is exactly the behaviour utilised in the development of high-filed superconducting magnets. During my PhD the highest continuous magnetic field produced by any magnet became a tape of REBCO. These have applications from medical imagining, power generation, and green transport alternatives. The area that I hope this research is assisting is the testing and manufacture of these REBCO tapes. The highly non-linear behaviour that we observe shows that certain aspects of high temperature superconductors' current carrying properties need very fine measurements to properly map and understand. |
| First Year Of Impact | 2020 |
| Description | Max Planck Institutes Stuttgart |
| Organisation | Max Planck Society |
| Department | Max Planck Institute for Solid State Research |
| Country | Germany |
| Sector | Academic/University |
| PI Contribution | Samples grown by MPI were processed by me to prepare them for high field measurements. Then low field measurements were performed to understand their properties and to have a thoroughly characterised their competition. After they were studied in Cambridge I took them to high field facilities and performed electrical transport measurements on them. The data from these experiment were analysed by me. |
| Collaborator Contribution | Our collaborators grew the crystals that our measurements were performed on. Our measurements require very clean samples and these are exceptional difficult to produce. The scientists at MPI Stuttgart have succeeded consistently at this. |
| Impact | Most of the results described in the academic achievements sections would not have been possible without high quality crystals as a starting point. I would consider this collaboration as multidisciplinary, because their chemistry skills are most relevant to our work while my implementation of physics experiments is most relevant to my contribution. |
| Start Year | 2018 |