Vortex Matter in Copper-Oxide Superconductors with Periodic Defects

Description

The talk will focus on understanding how strategically placed topological defects affect the arrangement of Abrikosov vortices in a superconductor. This involves creating a precise potential landscape that can pin the vortices in place. It is crucial to ensure that these vortices are magnetically coupled, and hence, their separation should not exceed the London penetration depth at the desired operating temperature. The latter should be significantly lower than the superconductor's critical temperature Tc to minimize the impact of thermodynamic fluctuations. Achieving nanoscale resolution is particularly challenging in copper-oxide superconductors due to their complex atomic structure and susceptibility to environmental influences. Traditional lithographic methods are limited in this context, but these challenges can be overcome using a focused beam from a helium ion microscope (He-FIB). The 30 keV He+ ion beam is employed to create various arrays of defect columns in thin films of YBa2Cu3O7-δ (YBCO). These nanocolumns suppress Tc due to pair-breaking caused by numerous point defects, making them effective pinning sites for Abrikosov vortices.

The distinctive layout of our pinning landscapes leads to several noteworthy phenomena. The interaction between vortex pinning at artificial regular and intrinsic irregular sites results in the creation of an ordered Bose glass of vortices [1,2]. A periodic pinning pattern with voids allows us to study the competition between pinning and elastic forces that seek to restore the genuine hexagonal vortex arrangement [3]. In ultradense hexagonal pinning landscapes, we observe reentrant zero resistance at an applied magnetic field of 3.8 T, accompanied by a pronounced peak in the pinning force density of the vortex ensemble caused by commensurability effects. When the vortex density aligns with the precisely known density of defect columns, we can determine the pinning force exerted on an individual vortex by an artificial defect. We will also discuss how this pinning force varies with temperature in the context of Ginzburg-Landau theory.

[1] L. Backmeister, B. Aichner, M. Karrer, K. Wurster, R. Kleiner, E. Goldobin, D. Koelle, W. Lang, Nanomaterials 12 (2022) 3491
[2] B. Aichner, L. Backmeister, M. Karrer, K. Wurster, R. Kleiner, E. Goldobin, D. Koelle, W. Lang, Condens. Matter 8 (2023) 32.
[3] B. Aichner, B. Müller, M. Karrer, V. Misko, F. Limberger, K. L. Mletschnig, M. Dosmailov, J. D. Pedarnig, F. Nori, R. Kleiner, D. Koelle, W. Lang, ACS Appl. Nanomater., 2 (2019) 5108.

Acknowledgments
The research was funded by a joint project of the Austrian Science Fund (FWF), grant I4865-N, and the German Research Foundation (DFG), grant KO 1303/16-1. It is based upon work from COST Actions CA19140 (FIT4NANO), CA21144 (SuperQuMap), and CA19108 (Hi-SCALE) supported by COST (European Cooperation in Science and Technology).

Period	2 Oct 2024
Event title	10th International Conference on Materials Science and Condensed Matter Physics
Event type	Conference
Location	Chișinău, Moldova, Republic ofShow on map
Degree of Recognition	International