Alberto Riminucci, Mirko Prezioso, Chiara Pernechele, Patrizio Graziosi, Ilaria Bergenti, Raimondo Cecchini, Marco Calbucci, Massimo Solzi, Alek Dediu
We investigated the spin precession (Hanle effect) in the prototypical organic spintronic device La0.7Sr0.3MnO3/Alq3/AlOx/Co. This device possesses memristive properties, that is its resistance depends on the history of the applied voltage. Measurements were taken by applying a magnetic field at different angles theta from the plane of the device and in two different memristive states. In the limit of completely decoherent transport, the Hanle effect affects the giant magnetoresistance (GMR) of these devices by decreasing it in proportion to cos^2(theta); no such dependence was detected. We rule out contribution from the tilting out of plane of the magnetization of the electrodes by analyzing their magnetization curves. On the other hand, the explanation of the results with the high velocity of the carriers would require a mobility of 30 cm^2 V^-1 s^-1 in the organic semiconductor. This is more than one order of magnitude greater than the maximum reported for Alq3. Our results call for a greater understanding of spin transport in these devices.
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http://arxiv.org/abs/1211.3986
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