Room-temperature spin-dependent tunneling through molecules

We have fabricated assemblies of molecular junctions comprised of superparamagnetic Fe(3)O(4) nanoparticles self-assembled with alkane molecules of different lengths as the spacer. The electrical resistance increases exponentially over nearly two decades as the molecular length varies from 0.7 to 2.5 nm, indicating that electrons tunnel through the molecules that are chemically bonded with Fe(3)O(4) nanoparticles. Up to similar to 21% room-temperature magnetoresistance is observed. Remarkably, the tunneling magnetoresistance ratio stays nearly independent of molecular length, which entails room-temperature spin-conserving transport in organic molecules. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3583585]