Josephson Junction with a Magnetic Vortex

We have studied Josephson tunneling through a circularly polarized micron or submicron-size disk of a soft ferromagnetic material. Such a disk contains a vortex that exhibits rich classical dynamics and has recently been proposed as a tool to study quantum dynamics of the nanoscale vortex core. The change in the Josephson current that is related to a tiny displacement of the vortex core has been computed analytically and plotted numerically for disks used in experiments. It is shown that a Josephson junction with a magnetic disk in the vortex state can be an interesting physical system that may be used to measure the nanoscale motion of the magnetic vortex.