Authors: Max Karrer, Bernd Aichner, Katja Wurster, César Magén, Christoph Schmid, Robin Hutt, Barbora Budinská, Oleksandr V. Dobrovolskiy, Reinhold Kleiner, Wolfgang Lang, Edward Goldobin, and Dieter Koelle
Abstract: Controlled engineering of vortex pinning sites in copper-oxide superconductors is a critical issue in manufacturing devices based on magnetic flux quanta. To address this, we employed a focused He-ion beam (He-FIB) to irradiate thin YBa2Cu3O7−δ films and create ultradense hexagonal arrays of defects with lattice spacings as small as 20 nm. Critical current and magnetoresistance measurements demonstrate efficient pinning by a matching field of 6 T visible in a huge temperature range from the critical temperature Tc down to 2 K. These results show that He-FIB irradiation provides excellent opportunities for the development and application of superconducting fluxonic devices based on Abrikosov vortices. In particular, our findings suggest that such devices can operate at temperatures far below Tc, where superconductivity is robust.
