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The field of fluxtronics is based on transmitting and processing information using quanta of magnetic flux in a type-II superconductor. In this study, temperature is used to reversibly tune the energy landscape of flux vortices pinned in a patterned sample of YBa${}_{2}$Cu${}_{3}$O${}_{7}$, providing an avenue to thermally switchable device functionalities. This nanopatterning method could also be applied to other oxide materials, such as ferromagnets or ferroelectrics, to possibly extend the concept of temperature-dependent functionality.

We have developed a masked ion irradiation technique to engineer the energy landscape for vortices in oxide superconductors. This approach associates the possibility to design the landscape geometry at the nanoscale with the unique capability to adjust the depth of the energy wells for vortices. This enabled us to unveil the key role of vortex channeling in modulating the amplitude of the field matching effects with the artificial energy landscape, and to make the latter govern flux dynamics over an unusually wide range of temperatures and applied fields for high-temperature superconducting films.

Using heterostructures that combine a large-polarization ferroelectric (BiFeO3) and a high-temperature superconductor (YBa2Cu3O(7-δ)), we demonstrate the modulation of the superconducting condensate at the nanoscale via ferroelectric field effects. Through this mechanism, a nanoscale pattern of normal regions that mimics the ferroelectric domain structure can be created in the superconductor. This yields an energy landscape for magnetic flux quanta and, in turn, couples the local ferroelectric polarization to the local magnetic induction. We show that this form of magnetoelectric coupling, together with the possibility to reversibly design the ferroelectric domain structure, allows the electrostatic manipulation of magnetic flux quanta.

We report on the effects of small miscuts of the (001) SrTiO 3 (STO) substrate surface, on the microstructure of epitaxial films of YBa 2 Cu 3 O 7 - δ and NdBa 2 Cu 3 O 7 - γ (NBCO). The most noticeable result is that, by growing NBCO films on miscut STO substrates with the steps intentionally oriented along a direction within 15° of [110], one reliably obtains NBCO films with a single [110] twinning variant (the [110] is completely eliminated), which is a precious characteristic for all applications involving flux flow.