Imaging spin transport in a semiconductor with an iron-filled carbon nanotube

There has been much recent progress in the field of spintronic device fabrication, creating a need for characterization tools. We are developing a low-temperature scanned probe microscope with the ability to position, with high precision, a magnetized iron-filled carbon nanotube above a spin-injected semiconductor device [1]. The inhomogeneous field of this unique magnetic probe will be experienced by spins in the sample. We have developed a technique for simulating the effects of such an inhomogeneous field [2]. Crucially, we find that our scanned probe technique can create highly localized spin density features on a length scale comparable to the nanotube diameter. This will allow for spatial mapping of the spin density with high resolution -- a capability not possible in current electrical detection schemes. Such experiments may provide information about interface effects, scattering, and material properties which influence spin behavior. \\[4pt] [1] F. Wolny, et al. J. Appl. Phys. 104, 064908 (2008)\\[0pt] [2] V. Bhallamudi, et al. arXiv:1010.3747v1 [cond-mat.mes-hall]