Bag, Biplab and Shaw, Gorky and Banerjee, SS and Majumdar, Sayantan and Sood, AK and Grover, AK (2017) Negative velocity fluctuations and non-equilibrium fluctuation relation for a driven high critical current vortex state. In: Scientific Reports, 7 (1). ISSN 2045-2322
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Abstract
Under the influence of a constant drive the moving vortex state in 2H-NbS2 superconductor exhibits a negative differential resistance (NDR) transition from a steady flow to an immobile state. This state possesses a high depinning current threshold {Ich) with unconventional depinning characteristics. At currents well above Ich, the moving vortex state exhibits a multimodal velocity distribution which is characteristic of vortex flow instabilities in the NDR regime. However at lower currents which are just above Ich, the velocity distribution is non-Gaussian with a tail extending to significant negative velocity values. These unusual negative velocity events correspond to vortices drifting opposite to the driving force direction. We show that this distribution obeys the Gallavotti-Cohen Non-Equilibrium Fluctuation Relation (GC-NEFR). Just above Ich, we also find a high vortex density fluctuating driven state not obeying the conventional GC-NEFR. The GC-NEFR analysis provides a measure of an effective energy scale (E eff ) associated with the driven vortex state. The E eff corresponds to the average energy dissipated by the fluctuating vortex state above Ich. We propose the high E eff value corresponds to the onset of high energy dynamic instabilities in this driven vortex state just above Ich.
| Item Type: | Journal Article |
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| Publication: | Scientific Reports |
| Publisher: | Nature Publishing Group |
| Additional Information: | The Copyright of this article belongs to the Authors. |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 03 Jun 2022 05:50 |
| Last Modified: | 03 Jun 2022 05:50 |
| URI: | https://eprints.iisc.ac.in/id/eprint/72960 |
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