Spin-dependent Quantum Interference in Single-Wall Carbon Nanotubes with Ferromagnetic Contacts

H. T. Man, I. J. W. Wever, A. F. Morpurgo

Published 2005-12-20, updated 2006-06-18Version 2

We report the experimental observation of spin-induced magnetoresistance in single-wall carbon nanotubes contacted with high-transparency ferromagnetic electrodes. In the linear regime the spin-induced magnetoresistance oscillates with gate voltage in quantitative agreement with calculations based on a Landauer-Buttiker model for independent electrons. Consistent with this interpretation, we find evidence for bias-induced oscillation in the spin-induced magnetoresistance signal on the scale of the level spacing in the nanotube. At higher bias, the spin-induced magnetoresistance disappears because of a sharp decrease in the effective spin-polarization injected from the ferromagnetic electrodes.