Mesoscopic EMR Device Magnetic Sensitivity in $I$ –$V$–$I$ –$V$ Configuration

Extraordinary magnetoresistance devices with critical dimensions below 50 nm have been developed in InAs 2-D electron gas (2DEG) quantum well heterostructures, and show the same magnetic sensitivity as Giant magnetoresistance magnetic recording sensors. A new device design, in which fingers of metal extend into the semiconductor mesa to form leads, yields higher signal and operating currents than the more conventional design with semiconductor tab contacts. Devices built with the 2DEG very close to the surface yield high-signal and high-current carrying capacity, as required for scanning probe and magnetic recording applications.