High-resolution magnetic image by high-Tc SQUID probe microscope

A superconducting quantum interference device (SQUID) probe microscope with a fine needle has been developed. The set-up has been designed to enable the SQUID probe microscope to measure samples in air and at room temperature. In order to demonstrate its ability for spatial resolution, it was used to observe laser printer letters. Fine toners with diameter of about one micron were observed clearly around the letter pattern, this confirmed that the technique has spatial resolution of less than a few microns.