Two-dimensional large-size Y Ba₂Cu₃O₇films (30 × 10 cm²) on CeO₂-buffered sapphire by a coating pyrolysis process

Abstract

Large-size, two-dimensional Y Ba2Cu3O7 (YBCO) films were successfully prepared by a chemical solution-based coating pyrolysis (CP) process on 30 × 10 cm2 R-plane sapphire substrates with a vacuum-deposited CeO2 buffer layer. The CeO2 layer was very smooth and uniform with an average roughness (Ra) of 0.48 nm by atomic force microscopic observations and highly (001)-oriented by large-area x-ray diffraction θ–2θ scans. The c-axis-oriented YBCO films were prepared by a CP process using a fluorine-free, metal acetylacetonate-based coating solution. A 30 × 10 cm2-rectangular c-axis-oriented YBCO film annealed in a large-diameter tube furnace demonstrated high inductive-Jc values, for which the distribution was fairly uniform, with an average 1.0 MA cm−2 at 77 K.

Influence of Impurity of MgO Substrates on Properties of Molecular Beam Epitaxy-Grown Superconducting NdBa2Cu3O7-δ Thin Films

“…Another option is to adopt a different substrate such as sapphire or a CeO 2 buffer layer on sapphire. 5) In such a case, we have to take account of the anisotropy of sapphire. Therefore annealed MgO seems to be the best choice as the substrate for practical microwave applications.…”