Shunt Effects In The Extraordinary Magnetoresistance (EMR) Of Macroscopic And Mesoscopic Devices
Abstract
From previous studies of EMR exhibited by semiconductor-metal composite structures(S.A. Solin et al., Science 289), 1530 (2000). it has been inferred that the magnetotransport properties of an EMR device depends critically on the geometry of the metallic shunt. We confirm this hypothesis by examining both macroscopic and mesoscopic shunted van der Pauw (VDP) plates. The EMR of the former is strongly dependent on the filling factor which is a complex function of the shunt geometry. So too is the EMR of the latter. We compare the EMR of mesoscopic plates constructed with and without a Au shunt and find maximal current sensitivities of 596.5 Ohm/T and 400.0 Ohm/T with EMR values of 7.5% and 4.8%, respectively at a signal field of 0.05T and a bias of 0.2T. This improvement over previously reported 147 Ohm/T devices(S.A. Solin et al., Appl. Phys. Lett. 80), 4012 (2002). results from a lowering of leakage current through the quantum well barrier due to the isolation of the contact electrodes with an aluminum oxide layer and a higher barrier resistivity.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2003
- Bibcode:
- 2003APS..MARD29004S