Epitaxy of thick (typically a few microns) high-Tc superconducting (HTS) films with on metal substrates is desired for coated conductor applications. Despite the "typical" degradation of the critical current (Jc) at large film thickness on single crystal oxide substrates, thick film coated conductors suffer more significant Jc loss at comparable thickness. This motivated us to investigate effects of in-plane and out-of-plane misorientations on the thickness dependence (bottom up) and depth dependence (top down) of Jcs. Bi-crystals with pre-defined grain boundary angles are employed for controlling the in-plane misorientation, and miscut substrates with different miscut angles for controlling the out-of-plane misorientation. Several different types of HTS thick films including YBa-2Cu-3O-7 (YBCO), Tl-2Ba-2CaCu-2O-(7+d) (Tl-2212), HgBa-2CaCu-2O-(6+d) (Hg-1212) will be investigated. By comparing materials with different anisotropy that may affect the thickness dependence of Jcs, we intend to pinpoint the dominant mechanisms that are responsible for the degradation of the Jc in HTS thick film coated conductors.
展开▼
