Commensurability effects in overlap Josephson junctions coupled with a magnetic dots array

TL;DR

This paper reports experimental evidence that an array of ferromagnetic nanodots significantly influences the critical current of a Josephson junction, revealing commensurability effects and vortex-induced phase inhomogeneities.

Contribution

It demonstrates the impact of magnetic nanodot arrays on Josephson junction behavior and explains the observed effects through vortex trapping and phase inhomogeneity.

Findings

Detection of pronounced commensurability effects in diffraction patterns

Observation of additional peaks due to magnetic nanodots

Attribution of pattern changes to Abrikosov vortex trapping

Abstract

Experimental observation of the strong influence of an array of ferromagnetic nanodots on the critical current of a short overlap Josephson junction is reported. Pronounced commensurability effects are detected due to the presence of the additional peaks in the magnetic field induced diffraction pattern. The changes in the Fraunhofer pattern of the Josephson junctions are account for by the formation of Abrikosov vortices trapped in the electrodes which induce a phase inhomogeneity in the junction area.