Windowless High-Tc Superconducting Quantum Interference Device Microscope

Abstract
A high-T c superconducting quantum interference device (SQUID) microscope with a sample chamber isolated by a shutter gate was designed and constructed for imaging samples at both room temperature and 77 K. According to our scheme, the separation of the sample from the SQUID can be less than several micrometers, in principle. We have successfully imaged a trapped flux in a YBa2Cu3O7-y thin-film ring at 77 K.