Rising Speed Limits for Fluxons via Edge-Quality Improvement in Wide MoSi Thin Films

Author(s)
Barbora Budinská, B. Aichner, D. Yu Vodolazov, M. Yu Mikhailov, F. Porrati, M. Huth, A. V. Chumak, W. Lang, O. V. Dobrovolskiy
Abstract

Ultrafast vortex motion has recently become a subject of extensive investigations, triggered by the fundamental question regarding the ultimate speed limits for magnetic flux quanta and enhancements of single-photon detectors. In this regard, the current-biased quench of a dynamic flux-flow regime—flux-flow instability (FFI)—has turned into a widely used method for the extraction of information about the relaxation of quasiparticles (unpaired electrons) in a superconductor. However, the large relaxation times 𝜏𝜖 deduced from FFI for many superconductors are often inconsistent with the fast relaxation processes implied by their single-photon counting capability. Here, we investigate FFI in 15-nm-thick 182-𝜇⁢m-wide MoSi strips with rough and smooth edges produced by laser etching and milling by a focused ion beam. For the strip with smooth edges we deduce, from current-voltage (𝐼-𝑉) curve measurements, a factor of 3 larger critical currents 𝐼𝑐, a factor of 20 higher maximal vortex velocities of 20 km/s, and a factor of 20 shorter 𝜏𝜖. We argue that for the deduction of the intrinsic 𝜏𝜖 of the material from the 𝐼-𝑉 curves, utmost care should be taken regarding the edge and sample quality and such a deduction is justified only if the field dependence of 𝐼𝑐 points to the dominating edge pinning of vortices.

Organisation(s)
Nanomagnetism and Magnonics, Electronic Properties of Materials
External organisation(s)
Russian Academy of Sciences, National Academy of Sciences of Ukraine (NASU), Johann Wolfgang Goethe-Universität Frankfurt am Main, Vienna Doctoral School in Physics
Journal
Physical Review Applied
Volume
17
No. of pages
12
ISSN
2331-7019
DOI
https://doi.org/10.1103/PhysRevApplied.17.034072
Publication date
03-2022
Peer reviewed
Yes
Austrian Fields of Science 2012
103033 Superconductivity, 103018 Materials physics
Keywords
ASJC Scopus subject areas
Physics and Astronomy(all)
Portal url
https://ucrisportal.univie.ac.at/en/publications/rising-speed-limits-for-fluxons-via-edgequality-improvement-in-wide-mosi-thin-films(ce434ff3-eb9b-4666-8c70-61e46995bbe7).html