Superresolution magnetic imaging by a Josephson junction via holographic reconstruction of Ic (H) modulation

Abstract

This work provides a proof-of-concept for superresolution magnetic imaging using a single Josephson junction. The technique resembles digital holography: magnetic patterns are obtained via an inverse-problem solution from diffractionlike modulation of the junction's critical current, Ic(H). We demonstrate numerical reconstruction of complex two-dimensional patterns, verify the technique experimentally using Nb-based planar junctions, and fabricate an operational sensor on a cantilever. Our results show that Josephson holography allows for both high spatial resolution (approximately 20nm) and high field sensitivity (approximately 10-11T/Hz), thus resolving the trade-off problem between resolution and sensitivity in magnetic scanning probe imaging.