Strong influence of the oxygen stoichiometry on the vortex bundle size and critical current densities Jc of GdBa2Cu3Ox coated conductors grown by co-evaporation

N. HABERKORN; J. GUIMPEL; S. SUAREZ; H. TROIANI; P. GRANELL; F. GOLMAR; JAE-HUN LEE; S. H. MOON; JAE-HUN LEE

SUPERCONDUCTOR SCIENCE AND TECHNOLOGY

IOP PUBLISHING LTD

Lugar: Londres; Año: 2017 vol. 30 p. 95009 - 95014

0953-2048

We report on the influence of oxygen stoichiometry in the vortex creep mechanisms of GdBa2Cu3Ox coated conductors produced by co-evaporation. The oxygen stoichiometry of the films, x, was modified in a controlled way between 6.85 and 7, which resulted in a systematic and reversible control of the superconducting critical temperature between aprox. 78 K to 93 K. The change in the oxygen stoichiometry produces a strong reduction of the self-field critical current densities Jc without significantly modifying the power-law dependence at intermediate magnetic fields, which indicates a negligible contribution of oxygen vacancies to the pinning. In addition, the characteristic glassy exponent u shows a systematic diminution from 1.63, at x = 7, to 1.12, at x = 6.85. The results are compared with those obtained for proton and oxygen irradiated films, in which the vortex dynamics is determined by a balance between the improved pinning, originated by nanocluster inclusion, and the suppressed superconducting properties due to disorder in the nanoscale.