Speaker
Description
Within the last decades, researchers from all over the world have been demonstrating the fascinating abilities of RE Ba2Cu3O7-δ (Rare Earth=RE) coated conductors (CC) to improve our day-to-day lives. However, among all large-scale applications, the prospect of acquiring energy from fusion power plants may well be the most breath-taking one. The main characteristic of RE BCO CC, which allows such wonders, is the ability to carry large amount of currents. Therefore, in order to acquire the best characteristics of such technologies and most compact designs, it is of utmost importance for material scientists to understand how the highest critical current density (Jc) of RE BCO superconducting layer may be achieved.
In RE BCO-based superconducting thin films Jc strongly depends on the interaction of vortices with defects present and, therefore, over the years the main strategy for enhancing Jc was implementation of additional nano-sized defects by various techniques. The most prominent among those is the introduction of artificial pinning centres (APC). In our recent work on the oxygen annealing of PLD-grown GdBa2Cu3O7-δ (GdBCO) superconducting thin films [1], we have shown that the defect morphology may be tailored via either decomposing Gd2O3 nanoparticles (NP) or stacking faults (SF) by varying the annealing temperature (Tann) and the oxygen pressure (P O2). Therefore, as a next step of pushing Jc we are combining two approaches: usage of mixed phase Y0.5Gd0.5Ba2Cu3O7-δ (YGdBCO) thin films and oxygen annealing. To do so, first the deposition conditions for PLD-grown YGdBCO thin films will be optimized. Secondly, YGdBCO thin films will be annealed in a tubular furnace at various Tann and P O2, similarly to GdBCO thin films from our previous work [1]. Structural and transport properties of YGdBCO superconducting thin films will be discussed compared to pristine GdBCO thin films. The similarities and differences of in-field Jc, anisotropy of Jc, and the defect morphology will be discussed.
References:
[1] Popov, R. “Influence of oxygen annealing on structural and transport properties of pristine and BaHfO3 nanocomposite GdBa2Cu3O7−δ films”. PhD thesis. Karlsruhe Institut für Technologie (KIT), 2023. 157 pp.
| Submitters Country | Germany |
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