Dresden 2003 – wissenschaftliches Programm

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SYHN: Hybrid nanostructures

SYHN 1: Hybrid Nanostructures

SYHN 1.1: Hauptvortrag

Donnerstag, 27. März 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).