Room temperature spin polarized injection in organic semiconductor

Spintronics is a new branch of electronics based on purely quantum effects. Instead of carrier charge transfer, as in usual electronics, it evokes carrier's spin transfer. The search of new materials suitable for injecting and transferring carriers with a preferential spin orientation is of paramount importance for the development of spintronics. Here we report a first experimental evidence of room temperature direct spin polarized injection in sexithienyl (T-6), a prototypical organic semiconductor, from colossal magnetoresistance manganite La0.7Sr0.3MnO3 (LSMO). A strong magnetoresistance (up to 30%) was measured on nanostructured planar hybrid junctions LSMO/T-6/LSMO. The spin diffusion length in T-6 is about 200 nm at room temperature. The results are discussed taking into account possible spin-flip mechanisms in organic material and interface effects. (C) 2002 Elsevier Science Ltd. All rights reserved.