Thin Films & Nanostructures


NbC directwrite

Vortex Matter & Dynamics

In strong collaboration with Oleksandr Dobrovolskiy (University of Vienna) we study the dynamics of Abrikosov vortices in tpye-II supercondcutors, e.g. at large transport currents. Under such far-from-equilibrium conditions the physics of current-driven vortex matter is getting especially interesting, as as sufficiently high vortex velocities other possible excitations in the system can be generated by the Cherenkov effect, such as sound and spin waves. This opens up novel routes to excite waves in magnon spintronics. Furthermore, there is currently great interest in the interplay of Meissner currents and magnetic flux quanta with spin waves in the domain of magnon fluxonics.

Josephson coupling and charging

Josephson-Coupled Systems

The cooperative ground state of a superconductor is characterized by phase coherence of its macroscopic wave function. Therefore, two superconductors brought in close contact, such as can be realized with a sufficiently transparent tunnel junction, show effects of phase coherence which can be controlled by a magnetic field. The associated dc and ac Josephson effects have technological relevance in highly sensitive magnetic flux sensors (SQUIDs). If the superconducting structures enter the nanoscale, along with the Josephson energy scale a second energy scale, namely the Cooper pair charging energy, enters the scene. We study various aspects of the interplay of Josephson and charging effects in superconducting nanostructures which we fabricate by direct-write techniques, such as FEBID or FIBID (focused ion beam induced deposition). This allows as to go from one-dimensional (1D), over two-dimensional (2D) to three-dimensional (3D) structures, as well as study Josephson networks, i.e. 1D or 2D arrays of Josephson-coupled superconductor nano-islands.