Journal article
Distinguishing between tunneling and injection regimes of ferromagnet/organic semiconductor/ferromagnet junctions
Physical review. B, Condensed matter and materials physics, Vol.81(19), 195214
05/2010
DOI: 10.1103/PhysRevB.81.195214
Abstract
Magnetoresistance effects in organic semiconductor spin valves have recently been reported, and have been variously interpreted as being due to tunneling magnetoresistance or giant magnetoresistance. We introduce a criterion for distinguishing between tunneling and injection conductivity necessary for properly analyzing organic spin-valve phenomena. We measure current-voltage (I−V) characteristics in Co/AlOx/rubrene/Fe junctions with a rubrene layer thickness, d, ranging from 5 to 50 nm. For d≤10 nm, the I−V traces are typical of tunnel junctions. At d>15 nm, the tunneling current becomes negligibly small. At larger biases, however, a second type of conductivity sets in. In this regime, the I−V curves are strongly nonlinear and temperature dependent. By comparing these to I−V curves measured in organic light-emitting diodes, we assign the latter mode to injection into the organic layer followed by hopping transport. We observe a spin-valve effect only in the tunneling regime.
Details
- Title: Subtitle
- Distinguishing between tunneling and injection regimes of ferromagnet/organic semiconductor/ferromagnet junctions
- Creators
- R Lin - University of IowaF Wang - University of IowaJ Rybicki - University of IowaM Wohlgenannt - University of IowaK. A Hutchinson - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Physical review. B, Condensed matter and materials physics, Vol.81(19), 195214
- DOI
- 10.1103/PhysRevB.81.195214
- ISSN
- 1098-0121
- eISSN
- 1550-235X
- Language
- English
- Date published
- 05/2010
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199785902771
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