title: Magnetoresistance in hybrid organic spin valves at the onset of multiple-step tunneling.
abstract: By combining experiments with simple model calculations, we obtain new insight in spin transport through hybrid, CoFeB/Al2O3(1.5 nm)/tris(8-hydroxyquinoline)aluminium (Alq3)/Co spin valves. We have measured the characteristic changes in the I-V behavior as well as the intrinsic loss of magnetoresistance at the onset of multiple-step tunneling. In the regime of multiple-step tunneling, under the condition of low hopping rates, spin precession in the presence of hyperfine coupling is conjectured to be the relevant source of spin relaxation. A quantitative analysis leads to the prediction of a symmetric magnetoresistance around zero magnetic field in addition to the hysteretic magnetoresistance curves, which are indeed observed in our experiments.
authors.affiliation: Department of Applied Physics, cNM, Eindhoven University of Technology, The Netherlands.
authors.forename: J J H M
authors.initials: JJ
authors.lastname: Schoonus
authors.forename: P G E
authors.initials: PG
authors.lastname: Lumens
authors.forename: W
authors.initials: W
authors.lastname: Wagemans
authors.forename: J T
authors.initials: JT
authors.lastname: Kohlhepp
authors.forename: P A
authors.initials: PA
authors.lastname: Bobbert
authors.forename: H J M
authors.initials: HJ
authors.lastname: Swagten
authors.forename: B
authors.initials: B
authors.lastname: Koopmans