Depth Profiling Photoelectron-Spectroscopic Study of an Organic Spin Valve with a Plasma-Modified Pentacene Spacer

[[abstract]]We report an enhanced magnetoresistance (MR) in an organic spin valve with an oxygen plasma-treated pentacene (PC) spacer. The spin valve containing PC without the treatment shows no MR effect, whereas those with moderately plasma-treated PC exhibit MR ratios up to 1.64% at room temperature. X-ray photoelectron spectroscopy with depth profiling is utilized to characterize the interfacial electronic properties of the plasma-treated PC spacer which shows the formation of a derivative oxide layer. The results suggest an alternative approach to improve the interface quality and in turn to enhance the MR performance in organic spin valves.[[incitationindex]]SCI[[booktype]]電子

Unravelling the role of the interface for spin injection into organic semiconductors

Whereas spintronics brings the spin degree of freedom to electronic devices, molecular/organic electronics adds the opportunity to play with the chemical versatility. Here we show how, as a contender to commonly used inorganic materials, organic/molecular based spintronics devices can exhibit very large magnetoresistance and lead to tailored spin polarizations. We report on giant tunnel magnetoresistance of up to 300% in a (La,Sr)MnO3/Alq3/Co nanometer size magnetic tunnel junction. Moreover, we propose a spin dependent transport model giving a new understanding of spin injection into organic materials/molecules. Our findings bring a new insight on how one could tune spin injection by molecular engineering and paves the way to chemical tailoring of the properties of spintronics devices.Comment: Original version. Revised version to appear in Nature Physics

Reliable prediction of giant magnetoresistance characteristics

Zhuravlev MY, Schepper W, Heitmann S, et al. Reliable prediction of giant magnetoresistance characteristics. PHYSICAL REVIEW B. 2002;65(14): 144428.We present a combined theoretical approach to the giant magnetoresistance (GMR) effect in magnetic multilayers which is able to provide good agreement with experimentally obtained GMR characteristics. This approach is based on a quantum statistical treatment, using as input the numerically determined orientation of the magnetic moments in the magnetic layers. It may be applied to determine spin-dependent transport properties, and to predict GMR characteristics for specific applications

Towards molecular spintronics: magnetotransport and magnetism in carbon nanotube-based systems

We describe first approaches towards a carbon nanotube (CNT) based spintronics. The building blocks consist of pristine wall CNTs and metallic ferromagnetic electrodes. The devices exhibit magnetoresistive effects up to several 10% at 4.2 K origin of which is tentatively attributed to spin-dependent tunneling through an insulating barrier between the CNT and electrode. We also show results of filling multi-wall CNTs with ferromagnetic materials. These magnetic quantum wires fascinating objects in itself, revealing unusual magnetic properties. They may also be used, however, as magnetic electrodes contact to the innermost shell of the nanotube in future molecular spintronics devices. (C) 2003 Elsevier B.V. All rights reserved