Lifeboat Foundation

A new technique reveals high-speed trajectories of oscillating vortices and shows that they are 10,000 times lighter than expected.

In many superconductors, applying a sufficiently strong magnetic field causes superconducting electrons to create current vortices that can be drawn along with a steady electric current. To learn more about how these vortices move, researchers have now visualized their trajectories in a situation where they are driven to oscillate at near-terahertz frequencies [1]. They observed the vortex motion on picosecond timescales and found that, under these conditions, a vortex’s effective mass is 10,000 times less than expected. This result may be important for efforts to improve high-current superconducting devices.

Superconductors can only deliver current up to a certain maximum value before the superconductivity is destroyed, which is an important concern for the development of high-current devices. Many researchers consider vortices—which can form even in the absence of an external magnetic field—to be the source of this so-called current-induced quenching. But determining how vortices cause quenching requires better knowledge of vortices and thus better measurements of their motion.