Investigation of the relationship of structure and transport properties of superconducting BiSrCaCuO thin films grown by metalorganic chemical vapor deposition
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
Thesis, Dissertation, English, 1998