Activation energy U(H) and pinning behavior of yb-impurity-diffused YBa2Cu3O7-x


PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, vol.204, no.10, pp.3478-3486, 2007 (SCI-Expanded) identifier identifier


Superconducting Y123 samples were prepared by the solid-state reaction (SSR) method. To get a layer of Yb (thickness similar to 4 pm) on the surface of one side of the sample art ultrahigh-vacuum electron-beam deposition system was used and Yb diffusion in Y123 was carried out thermally. The energy dispersive X-ray fluorescence technique (EDXRF) was used for the determination of the concentration of Yb atoms in the diffusion regions of Y123 samples. It was found that when the diffusing-annealing temperature increased the transition became much sharper and the sharpest transition was observed for the sample diffused at 900 degrees C. The activation energy of all samples was estimated from the resistivity curves using the TAFF model. It has been revealed that the pinning properties and activation energy improve when the diffusion-annealing temperature increases for a convenient temperature and also the activation energies of Yb-diffused samples are larger than that of an undoped Y123 sample. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim