Accelerated growth by flash heating of high critical current Trifluoroacetate solution derived epitaxial superconducting YBa2Cu3O7 films

Abstract

Trifluoroacetate solution derived epitaxial YBa2Cu3O7 films growth is a high throughput cost-effective approach to high critical current superconducting materials for power applications. Nonetheless, controlling the kinetic transformation of a multiphasic (Ba1-xYxF2+x, CuO) polycrystalline state to an epitaxial film requires preserving at the nanoscale the initial molecular homogeneity of the solutions. Here we present a flash heating approach (~ 30 times faster than conventional thermal annealing) to epitaxial films. We investigate through X-ray diffraction and TEM images the compositional and microstructural evolution at the nanoscale and we disclose how the nucleation rate is enhanced (3-5 times faster than conventional thermal annealing). We conclude that minimizing coarsening of the intermediate nanocrystalline phases has a very positive role in accelerating the total required growth process, as well as in decreasing the growth temperature to achieve a high quality epitaxy and microstructure. An additional advantage of the flash heating process is an increase of the density of nanometric defects (intergrowths), having a positive contribution to enhance vortex pinning efficiency and increasing the high magnetic field critical current density. Overall, implementing the flash heating process to grow YBa2Cu3O7 films appears as a very promising opportunity to reduce the cost / performance ratio of high temperature superconducting materials because it reduces the growth time and it enhances their performance.