Investigation of Abrikosov vortex phases in defect-engineered copper-oxide superconductors

Description

The study of how strategically placed topological defects influence the distribution of Abrikosov vortices in a superconductor hinges on the precise creation of a vortex-pinning potential landscape. It is essential to magnetically couple these vortices, ensuring their separation does not exceed the London penetration depth at the target operating temperature. This temperature must be substantially below the superconductor's critical temperature Tc to mitigate the effects of thermodynamic fluctuations. Achieving the necessary nanoscale precision is particularly challenging in copper-oxide superconductors due to their intricate atomic structure and sensitivity to environmental factors. Traditional lithographic methods face significant limitations in this context, but these can be circumvented by employing the focused beam of a helium ion microscope (He-FIB). The 30 keV He+ ion beam is utilized to create hexagonal arrays of defect columns in thin films of YBa2Cu3O7-δ and square arrays in Bi2Sr2CaCu2O8+x. Within these nanocolumns, Tc is suppressed due to pair-breaking caused by numerous point defects.
The unique topology of our pinning landscapes results in several notable phenomena. We observe vortex commensurability effects at high magnetic fields, reaching up to 6 T [1]. The interplay between vortex pinning at regular and intrinsic irregular sites leads to the formation of an ordered Bose glass of vortices [2,3]. Moreover, 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. When the vortex density aligns with the precisely known density of defect columns, the observation of commensurability effects enables us to determine the pinning force exerted on a single vortex by an artificial defect. We will also discuss how this pinning force varies with temperature.
Acknowledgments The research was supported by the Austrian Science Fund (FWF), grant I4865-N, the German Research Foundation (DFG), grant KO 1303/16-1, the Regional Gobierno de Aragón, Project No. E13_23R, and the EU Horizon 2020 programme, Grant No. 823717-ESTEEM3, and by the COST Actions CA21144 (SuperQuMap), CA19140 (FIT4NANO), and CA19108 (Hi-SCALE), funded by COST (European Cooperation in Science and Technology).
References
[1] Karrer Max et al., http://arxiv.org/abs/2404.05382.
[2] Backmeister Lucas et al., Nanomaterials, 12, 3491 (2022).
[3] Aichner Bernd et al., Condens. Matter 8, 32 (2023).

Period	13 Jun 2024
Event title	From Solid State to Biophysics XI
Event type	Conference
Location	Dubrovnik, CroatiaShow on map
Degree of Recognition	International