Correlation of Transport Properties with Grain Boundary Atomic Structure in High-{Tc} Superconducting Films and Tapes
Correlation of Transport Properties with Grain Boundary Atomic Structure in High-{Tc} Superconducting Films and Tapes

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Published: 1997

Total Pages: 5

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The critical current density of high-{Tc} superconducting thin films is found to be sensitive to the presence of flux-pinning defects, and particularly to the existence of grain boundaries which may act either as pinning centers for the vortices or as weak link junctions. Atomic resolution Z-contrast imaging and spatially resolved electron energy loss spectroscopy provide a method to obtain a direct image of the atomic grain boundary structure for correlation with its electronic structure. Using a combination of transport measurements and electron microscopy, the authors have begun to correlate superconducting properties with atomic scale grain boundary structure using YBCO thin films deposited on SrTiO3 bicrystals and on Ni substrates (RABiTS).

Investigation of the Relationship of Structure and Transport Properties of Superconducting BiSrCaCuO Thin Films Grown by Metalorganic Chemical Vapor Deposition
Investigation of the Relationship of Structure and Transport Properties of Superconducting BiSrCaCuO Thin Films Grown by Metalorganic Chemical Vapor Deposition

Author: Carolyn Renee Duran

Publisher:

Published: 1998

Total Pages:

ISBN-13:

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The effect of defects on the transport properties of $\rm Bi\sb2Sr\sb2CaCu\sb2O\sb{x}$ thin films were investigated. The film structural properties were altered through changes in the cation composition, He$\sp+$ ion irradiation, and controlled deposition on different substrates. Nearly phase-pure films were deposited over the composition range $\rm Bi\sb{1.8-3.4}Sr\sb{0.6-2.3}Ca\sb{0.6-1.9}Cu\sb{1.1-3.2}O \sb{x}.$ The presence of cation intermixing led to variations in the hole carrier concentration from 0.107-0.124 holes/Cu, as determined from the T$\rm\sb{c}.$ As the hole content decreased from 0.119 to 0.107 holes/Cu, the residual resistivity increased from $\sim$0-0.315 m$\Omega{\cdot}$cm, which was attributed to increased scattering by oxygen vacancies. Irradiation with 1 MeV He$\sp+$ ions systematically increased the oxygen vacancy concentration, leading to a residual resistivity increase from 50 to 2280 $\mu\Omega{\cdot}$cm at $10\sp{16}$ions/cm$\sp2.$ The increased residual resistivity was attributed to the segregation of displaced oxygen to domain boundaries in the film.