Probing and imaging spin interactions with a magnetic single-molecule sensor

Visualizing superexchange interactions The resolution that can be achieved in scanning probe microscopy can be greatly enhanced by absorbing a molecule such as CO on the probe tip. Czap et al. now show that this approach can be used to scan spin and magnetic properties of molecules on a surface. They adsorbed a magnetic molecule, Ni(cyclopentadienyl) 2 , on a silver surface and then transferred one of these molecules to a scanning tunnel microscope tip. They could then bring the tip toward the adsorbate-covered surface and map out the strength of superexchange interactions. Science , this issue p. 670