Real-space probing of the local magnetic response of thin-film superconductors using single spin magnetometry

TL;DR

This paper demonstrates real-space imaging of magnetic fields above a thin-film superconductor using single spin magnetometry, enabling direct measurement of local superconducting properties and supercurrents.

Contribution

It introduces a novel application of scanning single spin magnetometry for nanoscale magnetic characterization of thin-film superconductors.

Findings

Measured local London penetration depth.

Reconstructed supercurrents from magnetic field data.

Showed potential for high-temperature superconductor studies.

Abstract

We report on direct, real-space imaging of the stray magnetic field above a micro-scale disc of a thin film of the high-temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) using scanning single spin magnetometry. Our experiments yield a direct measurement of the sample's local London penetration depth and allow for a quantitative reconstruction of the supercurrents flowing in the sample as a result of Meissner screening. These results show the potential of scanning single spin magnetometry for studies of the nanoscale magnetic properties of thin-film superconductors, which could be readily extended to elevated temperatures or magnetic fields.