Our paper titled "Optimizing Nanocomposites through Nanocrystal Surface Chemistry: Superconducting YBa2Cu3O7 Thin Films via Low-Fluorine Metal Organic Deposition and Preformed Metal Oxide Nanocrystals" was accepted in Chemistry of Materials. DOI: 10.1021/acs.chemmater.7b02116
Thanks to a great collaboration with BASF SE, University of Turku, Deutsche Nanoschicht, Karlsruhe Institute of Technology and IFW Dresden!
Abstract: Achieving low cost, safe, reproducible, and high performance superconducting thin films of YBa2Cu3O7−δ is essential to bring this material to the energy market. Here, we report on the chemical solution deposition of YBa2Cu3O7−δ nanocomposites from environmentally benign precursors with a low fluorine content. Preformed ZrO2 nanocrystals (3.5 nm) were stabilized in a methanolic precursor solution via two strategies: charge stabilization and steric stabilization. Counterintuitively, charge stabilization did not result in high quality superconducting layers, while the steric stabilization resulted in highly reproducible nanocomposite thin films with a self-field Jc of 4–5 MA cm–2 (77 K) and a much smaller decay of Jc with magnetic field compared to YBa2Cu3O7−δ without nanocrystals. In addition, these nanocomposite films show a strong pinning force enhancement and a reduced Jc anisotropy compared to undoped YBa2Cu3O7−δ films. Given the relationship between the nanocrystal surface chemistry and final nanocomposite performance, we expect these results to be also relevant for other nanocomposite research.