Advancing the Current Carrying Capacity of TLAG YBCO Films: A Study on Overdoping and Vortex Pinning
PhD Candidate: Aiswarya Kethamkuzhi
Date: Thursday, 11 December 2025
Time: 10.30 AM
Venue: Sala d'Actes Carles Miravitlles and ONLINE (Register here)
Abstract
The development of high-temperature superconductors is one of the most ambitious achievements since the discovery of superconductivity, unlocking the vast potential of superconductors in contributing to technological advancements. Especially the high-temperature cuprate superconductors known as REBCO (REBa2Cu3O7−𝛿, RE = Rare Earth elements), in the form of coated conductors, are highly studied materials due to their exceptional superconducting properties, such as high critical current density and irreversibility field, which widen the window for large-scale applications of superconductors. However, there are still some challenges to overcome in the fabrication of high-performance coated conductors, amongst which the high cost/performance ratio is the prominent one.
The novel growth method developed at ICMAB for the fabrication of REBCO films is an ultrafast (growth rates up to 2000 nm/s) and cost-effective technique that combines Chemical Solution Deposition (CSD) with a non-equilibrium Transient Liquid Assisted Growth (TLAG) process. The TLAG method takes advantage of the high growth rate potential of liquid-mediated growth processes and aims to improve the cost/performance ratio for fabricating REBCO-coated conductors. In addition to reducing the manufacturing cost, enhancing the performance of coated conductors under an applied magnetic field is a crucial aspect.
Recently, an approach that is receiving more attention involves strategies to enhance condensation energy through the increase of charge carrier density by reaching the overdoped state in REBCO-coated conductors, where maximum critical current density can be achieved. Efforts are being made to address the challenge of overdoping in TLAG-CSD-grown films by means of different oxygenation methods and thereby modifying the electronic structure. The study highlights the ability of TLAG-grown REBCO films to achieve the overdoped state, and these findings will help lay the groundwork for future development of performance enhanced TLAG-coated conductors.
This thesis also delves into exploring the underlying microstructure generated by the ultrafast growth of TLAG and the mechanism of vortex pinning that gives rise to high critical current density. The nanoengineered TLAG films display greater potential than the pristine films, and we analyze them by correlating their microstructure with their physical properties. The primary outcome of this study is the understanding of the defect landscape of TLAG and how each defect predominates in a specific magnetic field temperature (H-T) regime. These findings imply a step forward in the fabrication of TLAG-coated conductors tailored for high magnetic field applications.
Supervisor
- Teresa Puig, ICMAB-CSIC
- Joffre Gutiérrez, ICMAB-CSIC
PhD Committee
- President: Pietro Massignan, UPC, Spain
- Secretary: Pablo Cayado, Universidad de Oviedo, Spain
- Vocal: Gaia Grimaldi, Institute for Superconductors, Innovative materials and Devices, Italy
University: Universitat Autònoma de Barcelona (UAB)
PhD Programme: Physics
