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Spin injection and transport in solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) are investigated using vertical CoPt/TIPS-pentacene/AlOx/Co spin valve architectures. The morphology and the molecular orientation of TIPS-pentacene spin-coated from a chloroform solution as grown in the spin valve devices are characterized by means of atomic force microscopy and x-ray diffraction, where the π-π stacking is found to be in planes oriented parallel to the substrate plane on CoPt (not L10-ordered). The magnetization hysteresis loops recorded with a superconducting quanmm interference device show an individual switching of the magnetization of the two ferromagnetic layers. The antiparallel state of the relative orientation of CoPt and Co is achieved due to their different coercive fields. A spin valve effect is observed at room temperature. The scaling of the magnetoresistance (MR) with the bulk mobility of TIPS-pentacene as a function of temperature together with the dependence of the MR on the interlayer thickness clearly indicates spin injection and transport in TIPS-pentacene. From organic semiconductor-spacer thickness-dependent MR measurements, we estimate a spin relaxation length of TIPS-pentacene of λs = (24 ± 6) nm and a spin relaxation time of approximately τs = 3.5 μs at r = 300 K, taking the measured bulk mobility of holes into account. [ABSTRACT FROM AUTHOR]

Transport measurements are presented on thin-film superconducting spin-valve systems, where the controlled noncollinear arrangement of twoferromagnetic Co layers can be used to influence the superconducting state of Nb. We observe a very clear oscillation of the superconducting transition temperature with the relative orientation of the twoferromagnetic layers. Our measurements allow us to distinguish between the competing influences of domain averaging, stray dipolar fields, and the formation of superconducting spin triplets. Domain averaging is shown to lead to a weak enhancement of transition temperature for the antiparallel configuration of exchange fields, while much larger changes are observed for other configurations, which can be attributed to drainage currents due to spin triplet formation. [ABSTRACT FROM AUTHOR]