NanoTP Scientists explore spin in doped nanotubes

Indirect Magnetic Coupling in Light-Element-Doped Single-Walled Carbon Nanotubes

A NanoTP collaboration between labs in Dublin, Nantes,Umeå, Delft, Orsay and Oslo has for the first time seen the signature of indirect magnetic coupling between low concentration light element impurities in single-walled carbon nanotubes.  The work represents collaboration between synthesis and characterisation groups, transport studies of individual tubes, coupled to density functional calculations of phosphorus and phosphorus oxide dopants.  It has recently appeared in "ACS Nano":

DOI: 10.1021/nn1009038
Publication Date (Web): August 4, 2010

Single-walled carbon nanotubes substitutionally doped with the light-element phosphorus are synthesized and are investigated by electrical and nuclear magnetic resonance measurements. Decreased spin−lattice relaxation times compared to undoped tubes point toward enhanced spin-sensitive scattering. Temperature dependence of the zero-bias conductance shows step-like features, a signature of scattering from a very low density (few sites per nanotube) of localized spin moments at oxidized phosphorus sites, consistent with density functional calculations. This supports recent predictions that localized magnetic moments must be indirectly magnetically coupled through the nanotube conduction electrons.

13 October 2010