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TT: Fachverband Tiefe Temperaturen
TT 35: Superconducting Electronics: SQUIDs, Circuit QED
TT 35.14: Talk
Wednesday, March 20, 2024, 13:00–13:15, H 2053
Nonlinear Conductivity in Superconductor MgB2 Films — •Clemens Schmid1, Markus Gruber1, Corentin Pfaff2, Karine Dumesnil2, Thomas Hauet2, Stephane Mangin2, and Oleksandr Dobrovolskiy1 — 1Faculty of Physics and Vienna Doctoral School in Physics, University of Vienna, Vienna, Austria — 2Université de Lorraine, CNRS, IJL, Nancy, France
Knowing the maximal vortex velocities is essential for assessing the energy relaxation mechanisms in superconductors and their applications in superconducting single-photon detectors (SSPDs) [1]. The dynamics of vortices at a few km/s velocities is furthermore interesting itself, because of the question regarding the ultimate speed limits for magnetic flux transport in superconductors and generation of sound and spin waves in heterostructures [2]. Here, we investigate the current-voltage curves of single crystal MgB2 20 nm-thick films which have comparably high critical temperatures of 30 K [3] and are interesting as potential materials for SSPDs. In the regime of nonlinear conductivity, we investigate the escape of non-equilibrium electrons from the vortex cores and compare the associated relaxation time of quasiparticles for MgB2 films of different structural quality and capped with a good-conductor (Au) layer. The deduced parameters are discussed in the context of crossover from global to local instability models and the application of MgB2 films in SSPDs [4].
[1] D. Vodolazov et al., Phys. Rev. Appl. 7 (2017) 034014
[2] O. Dobrovolskiy et al., Nat. Commun. 11 (2020) 3291
[3] M. Muralidhar et al., J. Phys. D: Appl. Phys. 57 (2023) 053001
[4] I. Charaev et al., arXiv 2308.15228 (2023)
Keywords: Superconductivity; Superconducting Single Photon Detectors; Magnesium diboride; Fluxonics