Coulomb blockade magnetoresistance in organic spin transport device*

Using buffer-layer-assisted growth, we successfully fabricated organic spin transport devices with a discontinuous granular magnetic layer centered in an organic spacer film. The Coulomb blockade magnetoresistance (MR) effects were observed, as predicted by X.-G. Zhang \textit{et al} (Phys. Rev. B. 81, 155122, 2010). The spin-dependent Coulomb blockade voltage arises from the coupled magnetic dots inside the organic material and correlate with the observed MR effect.