Investigation into Superconducting Y-Ba-Cu-O Films Containing Regions of Weak Superconductivity and Biased at I >> IC Stiprios I >> IC elektros srov s tankio pasiskirstymas plonuose Y-Ba-Cu-O sluoksniuose, turin iuose silpnojo superlaidumo sritis

Current distribution in YBa2Cu3O7-x superconducting thin film micro-bridges containing laser–written -shaped channel for easy vortex motion have been investigated in a narrow range of temperatures ranging from 85.7 to 90.2 K, which are below the critical temperature Tc of the material. In the range of the before mentioned temperatures the current-self magnetic field produced, Abrikosov magnetic vortices/anti-vortices appear in the partially deoxygenated (x ~ 0.2) channel and move coherently identifying itself as Josephson–like voltage “steps” in nonlinear current–voltage dependences. Bias current creates Lorentz force FL, pushing vortices along the LW-channel from its edges towards the centre. As follows from current-voltage dependences, vortices start moving at I = Ic. This current already satisfies condition FL >> Fp (where Fp – is pinning force in the film). Our results confirm that coherent vortex motion in the channel holds even at high biasing current when I ~ 200Ic. However, at these biasing currents, the width of voltage steps appears to be shorter than at lower current. This phenomenon has been explained by means of the onset of additional vortex motion in the laser untreated regions of the superconducting device. These regions are located in between the Π-shaped channel for easy vortex motion. Our results also demonstrate the possibility of investigating the electric properties of the mixed state superconductor by means of current dissipation due to the onset of coherent vortex motion. Article in Lithuanian Nagrin jamas elektros srov s pasiskirstymas YBa2Cu3O7-x superlaidininko plonuose sluoksniuose, kuriuose lazerio spinduliu suformuoti Π formos sūkuri kanalai. Superlaid iajame darinyje atsiradus sūkuri kanalui, srov s tankis lokaliose darinio vietose gali skirtis 5 ir daugiau kart , priklausomai nuo kanalo geometrijos. Darbe eksperimenti kai nustatyta, kad Abrikosovo magnetini sūkuri koherentinis jud jimas sūkuri kanale siaurame temperatūr ruo e nuo 85,1 K iki 90,2 K prasideda superlaid iuoju dariniu tekant I ~ Ic ir i lieka iki ypa stipri srovi I > 200I1st step. ia I1st step – srov s stipris, kuriam esant sūkuri kanale vyksta koherentinis sūkuri jud jimas, o Ic – kritin superlaidininko srov . Koherentinis sūkuri jud jimas kanalo srityje eksperimentuose pasirei kia darini voltamperin se charakteristikose elektros tampos laipteliais“, kuri auk tis beveik nepriklauso nuo dariniu tekan ios srov s stiprio. Eksperimentiniai rezultatai paai kinti koherentinio sūkuri jud jimo ypatumais Π formos sūkuri kanalu.