YingXiao Zhang

Deposition of Biaxially Textured

CeO₂ is considered as one of the most lattice matched and chemically stable material for YBa₂Cu₃O_7-x coated conductors. In this paper, the epitaxial growth of CeO₂ thin films on both the single crystal and the cube textured Ni5W substrates by MOD method were investigated. Homogeneous and crack-free CeO₂ thin films with sharp biaxially texture were obtained using the precursors made by both cerium ethylhexanoate and cerium acetate precursor solutions, followed by post-annealing at 1000-1150degC under flowing Ar-4%H₂ gas. The effects of the various precursors and the annealing parameters on the orientation and the roughness of the CeO₂ films on textured Ni5W substrate were discussed in detail.

{\rm CeO}_{2}

The key requirement for the substrates employed in coated conductors is using highly cube textured and weakly magnetic as well as strengthened materials. In this work, a tri-layer of composite substrate, as a substitute for the traditional substrate architecture, was designed and obtained by sintering two pieces of Ni-5at.% W (or Ni-7at.% W) outer layers on both sides of a Ni-12at.% W mixed powder (as an inner layer) together using an advanced spark plasma sintering (SPS) technology, followed by cold rolling and annealing. The sharp cube texture was obtained in both kinds of composite substrates by optimizing rolling and recrystallization processes. The percentage of the cube texture component on the Ni5W outer layer of the Ni5W/Nil2W/Ni5W composite substrate was higher than 95.4% within a misorientation angle of 10deg from EBSD measurements. Moreover, the yield strength of this composite substrate exceeds 300 MPa, while the saturation magnetization is reduced dramatically.

Thin Films on Single Crystal and Textured Ni5W Substrates Using Solution Derived Method

In this paper, we presented the results of YBCO films deposited epitaxially on both SrTiO3 single crystal and textured Ag substrates by a TFA-MOD method. The growing conditions and forming mechanisms of the YBCO films on these two kinds of substrates was investigated systematically. It was found that the precursor film coated on Ag substrate took less time to completely decompose to an amorphous precursor film during the first stage of the calcination than that on SrTiO3 substrate. Moreover, the higher temperature was needed to obtain pure YBCO phase on Ag substrate during the second annealing stage. A possible growing mechanism for this difference was described. A transport jc value of 1.5 x 104 A/cm2 (at 77 K) was obtained for the YBCO film deposited on Ag substrate, while the film on SrTiO3 substrate exhibited an a Tc onset of 92 K and a high jc value of 2.3 MA/cm2 at 77 K in self-field was measured.