Electromigration in YBCO superconducting nanostructures

Abstract

The compound YBa2Cu3O7-d (YBCO), the first superconductor with a critical temperature above the boiling temperature of liquid nitrogen, is widely studied due to its relative ease of fabricating and the uncertain origin of the mechanism that makes it a superconductor. In this compound, the oxygen vacancy concentration (d) changes its crystalline structure and, consequently, its superconducting properties. The material is not a superconductor for 0.7 < d < 1; however, for 0 < d < 0.7, it exhibits superconductivity with critical temperature also depending on d. In this scenario, recent investigations have shown that the electromigration technique - which consists of the atomic displacement due to high electric current densities - can modify the YBCO properties on the atomic scale. In this work, YBCO nanowires will be produced by both Solution Blow Spinning (SBS) and lithographed YBCO thin films grown by Pulsed Laser Deposition (PLD) in collaboration with researchers from UNESP-Ilha Solteira and the Brazilian Center for Research in Energy and Materials (CNPEM). Electromigration measurements will be performed in these nanowires to study the variation of their oxygen stoichiometry and its influence on their superconducting properties. For the structural analysis, we will use Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), and X-ray Diffraction (DRX).Furthermore, the new synchrotron light source SIRIUS, available at CNPEM, will be used to map the structural modifications caused by the electromigration. The electric and magnetic characterization will be done by varying the temperature and magnetic field conditions, with the flux distribution captured by Magneto-optical Imaging (MOI). Therefore, one can understand the effects of electromigration in YBCO in order to explore interesting features for several technological applications. (AU)