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Large Magnetoresistance at Room Temperature in Organic Semiconductor Sandwich Devices

Published online by Cambridge University Press:  01 February 2011

Govindarajan Veeraraghavan
Affiliation:
Department of Electrical & Computer Engineering, University of Iowa, Iowa City, Iowa-52242.
Omer Mermer
Affiliation:
Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa-52242.
Thomas Lee Francis
Affiliation:
Department of Electrical & Computer Engineering, University of Iowa, Iowa City, Iowa-52242.
Yugang Sheng
Affiliation:
Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa-52242.
Tho Duc Nguyen
Affiliation:
Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa-52242.
Markus Wohlgenannt
Affiliation:
Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa-52242.
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Abstract

We describe a recently discovered magnetoresistance (MR) effect in semiconducting polymer and small molecule sandwich devices. The MR effect reaches up to 10% in a magnetic field of 10mT at room temperature. This MR effect is therefore amongst the largest of any bulk material. We characterize this effect and discuss its dependence on voltage, film thickness, temperature, electrode materials and (unintentional) impurity concentration in three different organic semiconductors. We found that the MR effect is only weakly temperature dependent and does not depend on sign and direction of the applied magnetic field. To the best of our knowledge, the discovered MR effect is not adequately described by any of the mechanisms known to date.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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