6533b85dfe1ef96bd12be8e0
RESEARCH PRODUCT
Ray optics behavior of flux avalanche propagation in superconducting films
Yuri GalperinTom H. JohansenTom H. JohansenIlari MaasiltaPavlo MikheenkoS. Chaudhurisubject
superconducting filmsSuperconductivityShock wavePhysicsta114Condensed matter physicsdendritesta221FluxDissipationCondensed Matter PhysicsRefractionRayflux avalanchesElectronic Optical and Magnetic MaterialsElectrodeRefractive indexdescription
Experimental evidence of wave properties of dendritic flux avalanches in superconducting films is reported. Using magneto-optical imaging the propagation of dendrites across boundaries between a bare NbN film and areas coated by a Cu layer was visualized, and it was found that the propagation is refracted in full quantitative agreement with Snell's law. For the studied film of 170 nm thickness and a $0.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$ thick metal layer, the refractive index was close to $n=1.4$. The origin of the refraction is believed to be caused by the dendrites propagating as an electromagnetic shock wave, similar to damped modes considered previously for normal metals. The analogy is justified by the large dissipation during the avalanches raising the local temperature significantly. Additional time-resolved measurements of voltage pulses generated by segments of the dendrites traversing an electrode confirm the consistency of the adopted physical picture.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-02-23 | Physical Review B |