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Degree

Doctor of Philosophy, Ohio State University, Physics, 2011.

Abstract

Organic magnetoresistance is a phenomenon that is exhibited by many organic semiconductors. The resistance can change by more than 10 % at room temperature and as little as 10 milli-Tesla (mT) applied magnetic field. The change can be either positive or negative, and is angle invariant with respect to magnetic field orientation. Several theories have been presented to account for this anomalous magnetoresistance, but thus far the magnetoresistance by interconversion of singlets and triplets (MIST) model has been the most successful in explaining the behavior. Despite all the research that has gone into this effect, very few reports have gone to fields above 1 Tesla (T). In this manuscript, several specific predictions made by the MIST mechanism will be tested including qualitative behaviors and a quantitative fitting. Studies have been performed up to 35 T to explore the high field behavior. It will be demonstrated that for the low field regime, the MIST model is in excellent agreement with experiment, but that the high field regime is caused by a separate mechanism, not described by any current theory.

Subject Headings

Physics

Keywords

Organic semiconductors; magnetoresistance; recombination

Committee / Advisors

Arthur Epstein, PhD (Advisor)
David Stroud, PhD (Committee Member)
Jay Gupta, PhD (Committee Member)
Michael Lisa, PhD (Committee Member)
Jeffrey Lakritz, PhD (Committee Member)

Pages

76p.

Document number: osu1292530511
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=osu1292530511

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