Electric coupling in scanning SQUID measurements
Scanning SQUID is a local magnetometer which can image flux through its pickup loop due to DC magnetic fields (\(\Phi\)). Scanning SQUID can also measure a sample's magnetic response to an applied current (\(d\Phi/dI\)) or voltage (\(d\Phi/dV\)) using standard lock-in techniques. In this manusc...
Saved in:
Published in | arXiv.org |
---|---|
Main Authors | , , , , , , , |
Format | Paper Journal Article |
Language | English |
Published |
Ithaca
Cornell University Library, arXiv.org
18.12.2015
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Scanning SQUID is a local magnetometer which can image flux through its pickup loop due to DC magnetic fields (\(\Phi\)). Scanning SQUID can also measure a sample's magnetic response to an applied current (\(d\Phi/dI\)) or voltage (\(d\Phi/dV\)) using standard lock-in techniques. In this manuscript, we demonstrate that electric coupling between the scanning SQUID and a back gate-tuned, magnetic sample can lead to a gate-voltage dependent artifact when imaging \(d\Phi/dI\) or \(d\Phi/dV\). The electric coupling artifact results in \(d\Phi/dV\) and \(d\Phi/dI\) images which mimic the spatial variation of the static magnetic fields from the sample (e.g. ferromagnetic domains). In back-gated \(EuS/Bi_2Se_3\) bilayers, we show that the electric coupling effect is important, and is responsible for the reported signal from chiral currents in Y.H. Wang, et al. (DOI: 10.1126/science.aaa0508). Previous scanning SQUID current imaging experiments are unaffected by this artifact, as they are either on non-magnetic samples or the spatial distribution of magnetism does not match the features observed in \(d\Phi/dI\). In conclusion, \(d\Phi/dI\) or \(d\Phi/dV\) imaging of magnetic, back-gated samples should only be applied and interpreted with great caution. |
---|---|
ISSN: | 2331-8422 |
DOI: | 10.48550/arxiv.1512.03373 |