Optimizing Nanocomposites through Nanocrystal Surface Chemistry: Superconducting YBa2Cu3O7 Thin Films via Low-Fluorine Metal Organic Deposition and Preformed Metal Oxide Nanocrystals

• Published in: Chemistry of materials Vol. 29; no. 14; pp. 6104 - 6113
• Main Authors: Rijckaert, Hannes, Pollefeyt, Glenn, Sieger, Max, Hänisch, Jens, Bennewitz, Jan, De Keukeleere, Katrien, De Roo, Jonathan, Hühne, Ruben, Bäcker, Michael, Paturi, Petriina, Huhtinen, Hannu, Hemgesberg, Maximilian, Van Driessche, Isabel
• Format: Journal Article
• Language: English
• Published: American Chemical Society 25.07.2017
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.7b02116

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 J c of 4–5 MA cm–2 (77 K) and a much smaller decay of J c with magnetic field compared to YBa2­Cu3O7−δ without nanocrystals. In addition, these nanocomposite films show a strong pinning force enhancement and a reduced J c 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.