The Investigation of Vortex Motion in the YBCO Devices Manufactured Utilizing a Gaussian-shaped Optical Spot from a Continuous-wave Laser

Abstract

The current report focuses on the analysis of the investigation results of the Abrikosov vortex motion in the YBa2Cu3O7-d (YBCO) device, which is a c-axis textured 0.3 ´ 50 ´ 100 µm3 (thickness ´ width ´ length) stripe of YBCO superconductor deposited on a LaAlO3 substrate. A laser beam focused in a Gaussian-shape optical spot of 5 mm in diameter modifies the stripe, initiating the oxygen out-diffusion and its uneven distribution in illuminated areas and in this way causing the appearance of a higher level of deoxygenation in the spot center and a lower level at its edges (slopes of weak superconductivity region). At temperatures below the temperature of the superconducting transition Tc, the current-self-produced magnetic field penetrates the optically modified area of the stripe in a form of Abrikosov magnetic vortices, and due to the current-self-produced Lorentz force, the vortices move toward their annihilation line resulting in energy dissipation. The vortices pinned on the slopes experience strong pinning and exert a magnetic drag force on moving vortices, which is confirmed by the stepped current-voltage dependences of the YBCO devices measured at temperatures 0.933·Tc £ T £ 0.958·Tc. Our results demonstrate the advantages of partially deoxygenated YBCO material for the development of superconducting electronic devices with electronic properties controlled by the motion of Abrikosov vortices at temperatures below Tc of the superconductor.