Improving sol-gel Yba2Cu3O7−δ film morphology using high-boiling-point solvents

Abstract

The effect of high-boiling-point solvent addition on the morphology of low-p(O2) processed, sol-gel YBa2Cu3O7−δ (YBCO) films is discussed. Proper selection and addition of a high-boiling-point solvent prevents film roughening during precursor pyrolysis, while permitting at least a tenfold reduction in pyrolysis time compared to standard film processing in air or O2. Use of such solvents appears to increase film plasticity, avoiding elastic compressive stress related buckling. High-quality YBCO films on 〈100〉 LaAlO3 with a critical current density (Jc) ∼ 3–4 MA/cm2 at 77 K, are routinely crystallized with this new sol-gel process. Diethanolamine-based, sol-gel YBCO films deposited on sol-gel SrTiO3-buffered 〈100〉 Ni have Jc(77 K) > 1 MA/cm2, demonstrating a route toward all-sol-gel superconducting wires.