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Large magnetoresistance in nonmagnetic π-conjugated semiconductor thin film devices
Journal article   Peer reviewed

Large magnetoresistance in nonmagnetic π-conjugated semiconductor thin film devices

Ö Mermer, G Veeraraghavan, T. L Francis, Y Sheng, D. T Nguyen, M Wohlgenannt, A Köhler, M. K AL-SUTI and M. S Khan
Physical review. B, Condensed matter and materials physics, Vol.72(20), pp.205202.1-205202.12
11/01/2005
DOI: 10.1103/PhysRevB.72.205202

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Abstract

Following the recent observation of large magnetoresistance at room temperature in polyfluorene sandwich devices, we have performed a comprehensive magnetoresistance study on a set of organic semiconductor sandwich devices made from different π-conjugated polymers and small molecules. The study includes a range of materials that show greatly different chemical structure, mobility, and spin-orbit coupling strength. We study both hole and electron transporters at temperatures ranging from 10 K to 300 K. We observe large negative or positive magnetoresistance (up to 10% at 300 K and 10 mT) depending on material and device operating conditions. We discuss our results in the framework of known magnetoresistance mechanisms and find that none of the existing models can explain our results. © 2005 The American Physical Society.
Physics Condensed matter: electronic structure, electrical, magnetic, and optical properties Electrical properties of specific thin films Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures Exact sciences and technology Polymers; organic compounds

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