Low-Fluorine Ba-Deficient Solutions for High-Performance Superconducting YBCO Films

High-performing superconducting YBa2Cu3O7–x (YBCO) films are fabricated by a chemical solution deposition methodology through novel barium-deficient low-fluorine solutions. The precursor solutions, distinguished for being straightforward, inexpensive and eco-friendly, allow us to reduce the growing temperature of YBCO down to 750 °C. We investigated the influence of the growing temperatures on both the microstructure and superconducting properties of YBCO films by using conventional thermal annealing and flash-heating approaches. A clear correlation between the growing temperature (Tg) and the superconducting performance of the films was obtained with improved performances observed at low Tg.

Development of a Fluorine-Free Polymer-Assisted-Deposition Route for YBa2Cu3O7−x Superconducting Films

Polymer assisted deposition (PAD) was used as an environmentally friendly, non-fluorine, growth method for superconducting YBa2Cu3O7−x (YBCO) films. The kinetics of the thermal decomposition of the precursor powder was studied by thermogravimetry coupled with mass spectrometry (TG-QMS). YBCO films were spin coated on (100) SrTiO3 (STO) single crystalline substrates, followed by a single step thermal treatment under wet and dry O2 and O2/N2 mixture. The as-obtained films were epitaxially grown having a [001]YBCO||[001]STO out-of-plane epitaxial relationship and exhibited good superconducting properties with Tc (R = 0) > 88 K, transition widths, ΔT ≈ 2 K and critical current densities as high as 2.3 MA/cm2 at 77 K and self magnetic field.