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Spin Transport and Magneto-Resistance in Organic Semiconductors

Published online by Cambridge University Press:  31 January 2011

Mohammad Yunus
Affiliation:
[email protected], University of Minnesota, Electrical and Computer Engineering, 200 Union street SE, Minneapolis, Minnesota, 55455-0167, United States
P. P. Ruden
Affiliation:
[email protected], University of Minnesota, Minneapolis, Minnesota, United States
Darryl L. Smith
Affiliation:
[email protected], Los Alamos National Laboratory, Los Alamos, United States
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Abstract

Calculated results for spin injection, transport, and magneto-resistance (MR) in organic semiconductors sandwiched between two ferromagnetic contacts are presented. The carrier transport is modeled by spin dependent device equations in drift-diffusion approximation. In agreement with earlier results, spin injection from ferromagnetic contacts into organic semiconductors can be greatly enhanced if (spin-selective) tunneling is the limiting process for carrier injection. Modeling the tunnel processes with linear contact resistances yields spin currents and MR that tend to increase with increasing bias. We also explore the possibility of bias dependent contact resistances and show that this effect may limit MR to low bias.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

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