  The diamagnetic susceptibility of a superconductor is directly related to its
superfluid density. Mutual inductance is a highly sensitive method for
characterizing thin films; however, in traditional mutual inductance
measurements, the measured response is a non-trivial average over the area of
the mutual inductance coils, which are typically of millimeter size. Here we
image localized, isolated features in the diamagnetic susceptibility of
{\delta}-doped SrTiO3, the 2-DES at the interface between LaAlO3 and SrTiO3,
and Nb superconducting thin film systems using scanning superconducting quantum
interference device susceptometry, with spatial resolution as fine as 0.7
{\mu}m. We show that these features can be modeled as locally suppressed
superfluid density, with a single parameter that characterizes the strength of
each feature. This method provides a systematic means of finding and
quantifying submicron defects in two-dimensional superconductors.

Superconductivity