Development of high-<i>T</i>_cSQUID microscope with flux guide

Abstract

We have developed a new type of superconducting interference device (SQUID) microscope. A direct-coupled SQUID magnetometer with a high-μ metal needle was used and the substrate was machined to create a dimple for the needle at the centre of the pick-up loop. One end of the needle penetrated through the superconducting pick-up loop in a vacuum; the needle was fixed in the vacuum window with the other end at room temperature in the outside atmosphere. Several kinds of simulation using a Maxwell simulator were performed and the results were applied to our system. As a demonstration, a laser-printed output was scanned by the microscope. Line bars with a line width of 100 μm and a spacing between lines of 200 μm were clearly imaged.