Patterning damage in narrow trackwidth spin-valve sensors

Abstract

Using a combination of electron-beam lithography and Ar ion milling, we have fabricated spin-valve sensors with widths ranging from 30 to 250 nm. Although the resistance of the sensors scales as expected with width, the giant magnetoresistance (GMR) ratio decreases with decreasing width, consistent with the presence of a region with negligible GMR at the edges of the sensors. Sensors patterned using a focused ion beam showed a similar but much greater effect. We attribute this behavior to edge damage associated with the patterning process.