Tailoring Vortex Behavior in High-Tc Superconductors via Periodic Defects Created by Focused Helium Ion Beams

Description

The strategic placement of topological defects to control Abrikosov vortex distribution in superconductors relies on precisely engineered vortex-pinning landscapes. Effective magnetic coupling requires vortex separation within the London penetration depth at the operating temperature, which must be well below Tc to minimize thermodynamic fluctuations. Achieving nanoscale precision is particularly challenging in copper-oxide superconductors due to their complex atomic structure and environmental sensitivity. Traditional lithography is unsatisfactory, but irradiation with a focused helium ion beam (He-FIB) overcomes these limitations. A 30 keV He⁺ beam creates defect arrays in YBa₂Cu₃O₇₋_δ (Fig. 1a) and Bi₂Sr₂CaCu₂O₈₊ₓ thin films, where Tc is locally suppressed by pair-breaking from point defects.
The unique topology of our pinning landscapes induces notable effects, including vortex commensurability at record-high fields up to 6 T (Fig. 1b) [1] and vortex caging [2]. The coexistence of artificial and intrinsic pinning sites forms an ordered Bose glass of vortices [3]. We also observe reentrant zero resistance and strong vortex stiffness, resulting in the transverse Meissner effect (Fig. 1c). When vortex density matches the defect column density, commensurability effects allow us to quantify the pinning force on an individual vortex.

* 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 CA21144 (SuperQuMap), CA19140 (FIT4NANO), and CA23134 (PolyTopo).

[1] M. Karrer et al., Phys. Rev. Applied 22, 14043 (2024).
[2] B. Aichner et al. ACS Appl. Nano Mater. 2 5108 (2019).
[3] L. Backmeister et al., Nanomaterials, 12, 3491 (2022)

Period	11 Aug 2025
Event title	30th International Conference on Low Temperature Physics
Event type	Conference
Location	Bilbao, SpainShow on map
Degree of Recognition	International