We present a method, based on vortex imaging by low-temperature scanning electron microscopy (LTSEM), to directly image the sheet-current distribution in ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_7$ dc superconducting quantum interference device washers. We show that the LTSEM vortex signals are simply related to the scalar stream function describing the vortex-free circulating sheet-current distribution $\mathit{J}$. Unlike previous inversion methods that infer the current distribution from the measured magnetic field, our method uses pinned vortices as local detectors for $\mathit{J}$. Our experimental results are in very good agreement with numerical calculations of $\mathit{J}$.

• Received 16 September 2005

DOI:https://doi.org/10.1103/PhysRevB.73.064508