AbstractSpin coherent transport in carbon nanotubes enables single-nanotube devices for magnetic field sensing. This unique transport property of single walled carbon nanotubes (SWCNTs) has been studied for development into advanced sensors for nondestructive evaluation (NDE). Coupling of a single walled carbon nanotube to ferromagnetic electrodes is predicted to form a carbon nanotube magnetic tunnel junction. Fabrication of such devices has been performed through scanning probe and electron beam lithography. Purified single walled carbon nanotubes are deposited across electrodes to complete device fabrication. A spincoherent quantum transport theory based on a nonequilibrium Green's function method has been established to predict conductance and magnetoconductance across junctions. Experimental measurements of the room temperature conductance of Cobalt/SWCNT/Cobalt junctions have been performed.