We describe a new type of scanning probe microscope based on a superconducting quantum interference device (SQUID) that resides on the apex of a sharp tip. The SQUID-on-tip is glued to a quartz tuning fork which allows scanning at a tip-sample separation of a few nm. The magnetic flux sensitivity of the SQUID is 1.8 {\mu}_0/Hz^{1/2} and the spatial resolution is about 200 nm, which can be further improved. This combination of high sensitivity, spatial resolution, bandwidth, and the very close proximity to the sample provides a powerful tool for study of dynamic magnetic phenomena on the nanoscale. The potential of the SQUID-on-tip microscope is demonstrated by imaging of the vortex lattice and of the local AC magnetic response in superconductors.
@article{arxiv.1206.2853,
title = {Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena},
author = {A. Finkler and D. Vasyukov and Y. Segev and L. Ne'eman and E. O. Lachman and M. L. Rappaport and Y. Myasoedov and E. Zeldov and M. E. Huber},
journal= {arXiv preprint arXiv:1206.2853},
year = {2013}
}