The diamagnetic susceptibility of a superconductor is directly related to its superuid 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 measure localized, isolated features in the diamagnetic susceptibility of Nb superconducting thin films with lithographically defined through holes, δ-doped SrTiO3, and the 2D electron system at the interface between LaAlO3 and SrTiO3, using scanning superconducting quantum interference device susceptometry, with spatial resolution as fine as 0.7 μm. We show that these features can be modeled as locally suppressed superuid 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.
|Publication status||Published - 2018 Jun 2|
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