Magnetoresistance in organic spintronic devices: the role of nonlinear effects

We derive kinetic equations describing injection and transport of spin-polarized carriers in organic semiconductors with hopping conductivity via an impurity level. The model predicts a strongly voltage dependent magnetoresistance, defined as resistance variation between devices with parallel and an...

Full description

Saved in:
Bibliographic Details
Published in:New journal of physics 2015-02, Vol.17 (2), p.23019-9
Main Authors: Shumilin, A V, Kabanov, V V, Dediu, V A
Format: Article
Language:English
Subjects:
72.20.Ee
72.25.Dc
72.25.Hg
Charge transport
Devices
Electric potential
Hopping conduction
Kinetic equations
Magnetoresistance
Magnetoresistivity
Mathematical models
Nonlinearity
Organic semiconductors
Physics
Semiconductors
spin valve effect
Spin valves
spintronics
Voltage
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We derive kinetic equations describing injection and transport of spin-polarized carriers in organic semiconductors with hopping conductivity via an impurity level. The model predicts a strongly voltage dependent magnetoresistance, defined as resistance variation between devices with parallel and antiparallel electrode magnetizations (spin-valve effect). The voltage dependence of the magnetoresistance splits into three distinct regimes. The first regime matches well-known inorganic spintronic regimes, corresponding to barrier-controlled spin injection or the well-known conductivity mismatch case. The second regime at intermediate voltages corresponds to strongly suppressed magnetoresistance. The third regime develops at higher voltages and accounts for a novel paradigm. It is promoted by the strong nonlinearity in the charge transport whose strength is characterized by the dimensionless parameter eU/kBT. This nonlinearity, depending on device conditions, can lead to both significant enhancement or to exponential suppression of the spin-valve effect in organic devices. We believe that these predictions are valid beyond the case of organic semiconductors and should be considered for any material characterized by strongly nonlinear charge transport.
ISSN:1367-2630
1367-2630
DOI:10.1088/1367-2630/17/2/023019