HTS SQUID microscope head with sharp permalloy rod for high spatial resolution

Spatial resolution with a sharp permalloy rod on an HTS SQUID microscope head was investigated. A 5 mm diameter and 10 mm long permalloy rod with one side sharp and one side flat is placed In front of a washer type SQUID with 0.1 mm spacing. A 0.3 mm line and space meander line on a printed circuit board carrying current was used as a magnetic field source. The SQUID microscope head with the sharp permalloy rod scanned two dimensionally on the meander line inside the magnetic shield. The 0.3 mm line and space meander line was resolved. We also demonstrated imaging of laser-printed characters. This method has the advantage of using a washer type SQUID with high magnetic sensitivity, high spatial resolution and facilitating the adjustment of the position and the measurement distance from the sample