University of Twente Student Theses


Spin polarized tunneling in hybrid magnetic tunnel junctions comprising C60

Le, Quyen T. (2011) Spin polarized tunneling in hybrid magnetic tunnel junctions comprising C60.

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Abstract:Organic semiconductor spintronics has been extensively studied over the past decade due to the expectation of the exceptionally long spin lifetimes in carbon-based semiconductors. This prospective characteristic raises the hope for organic semiconductors as potential materials for developing spintronic applications such as spin based quantum computing and spin based organic light emitting diodes. Although spin transport in organic semiconductors is fascinating and potentially very useful, there are many challenges, both in understanding fundamental properties and, at a later stage, in obtaining high-quality devices. In this master project, carbon-based molecules (C60) were inserted into Co/Al2O3/NiFe magnetic tunnel junction structures to form vertical spin transport devices. By varying the C60 thickness from 0 to 20 nm, the vertical device geometry allows for the investigation of different spin-dependent transport regimes. Our results provide strong evidence of spin polarized tunneling as the dominant transport mechanism in C60-based magnetic tunnel junctions. Furthermore, based on the distinctive performance of devices with different C60 thickness, we can also identify between direct and two-step tunneling in junctions with 0–7 nm C60. This work presents the understanding of spin polarized transport in vertical organic spin transport devices. Moreover, we propose several approaches for further study to circumvent the conductivity mismatch problem and improve the efficiency of C60-based spin transport devices.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:33 physics
Programme:Nanotechnology MSc (60028)
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