Aging of electron-written YBCO superconducting thin film structures

The aging of Y1Ba2Cu3O7-delta thin film structures after low energy 30 keV electron irradiation has been investigated. The irradiation was aimed at creating artificial channels with suppressed superconductivity that would enforce the coherent flow of vortices. Through transport measurements, the irradiated regions were found to degrade gradually with the time of aging contrary to non-irradiated parts with good time stability of superconducting properties. Raman spectroscopy and atomic force microscopy investigations have revealed the presence of a relatively thick carbon contamination layer on the top of YBCO films originating from electron irradiation. X-ray photoelectron spectroscopy analysis supported by the evolution of Raman spectra suggests that carbon penetrating YBCO structures may be responsible for chemical interaction with the YBCO species to form C-O bonds, following the time evolution of the Raman spectra.