Giant magnetoresistance through a single molecule

Nat Nanotechnol. 2011 Mar;6(3):185-9. doi: 10.1038/nnano.2011.11. Epub 2011 Feb 20.

Abstract

Magnetoresistance is a change in the resistance of a material system caused by an applied magnetic field. Giant magnetoresistance occurs in structures containing ferromagnetic contacts separated by a metallic non-magnetic spacer, and is now the basis of read heads for hard drives and for new forms of random access memory. Using an insulator (for example, a molecular thin film) rather than a metal as the spacer gives rise to tunnelling magnetoresistance, which typically produces a larger change in resistance for a given magnetic field strength, but also yields higher resistances, which are a disadvantage for real device operation. Here, we demonstrate giant magnetoresistance across a single, non-magnetic hydrogen phthalocyanine molecule contacted by the ferromagnetic tip of a scanning tunnelling microscope. We measure the magnetoresistance to be 60% and the conductance to be 0.26G(0), where G(0) is the quantum of conductance. Theoretical analysis identifies spin-dependent hybridization of molecular and electrode orbitals as the cause of the large magnetoresistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cobalt / chemistry
  • Crystallization / methods
  • Electric Conductivity
  • Electric Impedance
  • Electrodes
  • Electronics / methods
  • Equipment Design
  • Feasibility Studies
  • Ferric Compounds / chemistry
  • Indoles / chemistry*
  • Magnetics* / instrumentation
  • Magnetite Nanoparticles / chemistry*
  • Materials Testing / methods
  • Microscopy, Scanning Tunneling
  • Nanotechnology / methods*
  • Signal Processing, Computer-Assisted

Substances

  • Ferric Compounds
  • Indoles
  • Magnetite Nanoparticles
  • ferrite
  • Cobalt
  • phthalocyanine