Superconducting nanoscale devicesfor on-chip generation and detection of microwave radiation

Date

May 3, 2019

Time

1:00 PM - 2:00 PM

Speaker

Prof. Oleksandr Dobrovolskiy

Affiliation

Physikalisches Institut, Goethe-Universität, Frankfurt am Main

Language

en

Main Topic

Materialien

Host

Kristina Krummer

Description

Most of superconductors in a magnetic field are penetrated by a lattice of quantized flux quanta, also known as Abrikosov vortices. In the presence of a transport current causing the vortices to cross sample edges, emission of electromagnetic waves is expected due to the continuity of tangential components of the fields at the surface. Usually, the radiated power levels are low because of small surface areas crossed by vortices and lacking coherence in the vortex motion. In my talk, I will present two approaches to detect microwave radiation from vortex motion in Nb films and Mo/Si superlattices. In the Nb films, a periodic nanowire antenna placed near the film surface allows for the detection of the ac voltage induced by coherently moving fluxons. As distinct from this, the internal periodicity of the structure itself is exploited for tuning the vortex dynamics into a coherent fashion resulting in robust microwave emission in the Mo/Si superlattice. In all, it will be demonstrated that the lattice of Abrikosov vortices in superconductors can act as a dc-tunable microwave generator bridging the frequency gap between conventional radiofrequency oscillators and (sub-)terahertz generators relying upon the Josephson effect. In addition, I will dwell on the interaction of the vortex lattice with spin waves in superconductor / ferromagnet hybrides [3] and the phenomenon of microwave-stimulated superconductivity in the vortex state [4].

Links

• Seminars at the IFW

Last modified: May 3, 2019, 6:26:02 PM