Dresden 2003 – scientific programme
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SYHN: Hybrid nanostructures
SYHN 1: Hybrid Nanostructures
SYHN 1.1: Invited Talk
Thursday, March 27, 2003, 09:30–10:10, HSZ/01
Extraordinary magnetoresistance in narrow-gap semiconductors: fundamental physics and practical applications — •Stuart Solin — Department of Physics, Washington University, St. Louis, Missouri, USA
Basic research on nonlinear transport in semiconductor superlattices led to the realization that narrow (zero)-gap
NON-MAGNETIC semiconductors may be competitive with or superior to MAGNETIC giant magnetoresistance (GMR)
structures, such as spin valves, for a number of magnetic sensor applications. Recently, we have measured, in narrow-gap
semiconductor/non-magnetic metal composites, the largest magnetoresistance yet reported for any system at room temperature [1]. We call this extraordinary magnetoresistance or EMR. Room temperature EMR in excess of 2000% at 0.05 Tesla and 3,000,000% at 5 T has been obtained
in non-biased macroscopic composite structures [2]. Following the quantitative explanation of the EMR phenomenon based on
geometric effects [1,2], much effort has been expended to scale EMR devices to the mesoscopic regime in order to impact
technologies such as ultra high density magnetic recording. The miniaturization of EMR devices has been successful [3] and has
revealed surprising new aspects of the mesoscopic physics of these composite structures. The potential impact of EMR on
magnetic sensor technology will be addressed.
[1] S.A. Solin et al., Science 289, 1530 (2000).
[2] T. Zhou, D.R. Hines, and S.A. Solin, Appl. Phys. Lett. 78, 667 (2001).
[3] S.A. Solin et al., Appl. Phys. Lett. 80, 4012 (2002).