Temperature Dependence of Magnetotransport in EMR Devices

Extraordinary magneto-resistance (EMR) devices have been fabricated and characterized at various magnetic fields, operating temperatures and current excitations. These devices are comprised of non-magnetic high mobility semiconductors and low resistance metallic contacts and shunts. The EMR devices were fabricated using two e-beam lithography processing. The completed EMR devices were tested between 300K and 5K in magnetic fields up to 5 T perpendicular to the 2DEG plane and excitation currents up to 100 A. EMR sensors for high density recording will have device structures smaller than the electron mean free path (mfp) in the full film semiconductor 2DEG. In this regime the electron transport is transitioning from diffusive to ballistic, and it is of scientific and practical interest to determine how the magnetic sensitivity evolves.