Abstract:

I will discuss recent progress in experimental techniques to control the orientations of nanoscale magnetic moments and electron spins, and to use these new means of control for applications.  One powerful new capability arises from the fact that thin magnetic layers can act as filters for spins.  During this filtering, spin-polarized currents can transfer some of their spin angular momentum to the magnetic layer, thereby applying a strong torque to the layer. The “spin-transfer torque” effect provides a very efficient means for manipulating the orientation of small magnets, capable of replacing magnetic fields in many applications.  In addition, it can give rise to interesting types of dynamical states in nanomagnets that are difficult to excite using magnetic fields alone.

I will also discuss experiments in which we are working toward extending the control of spins from the 100-nm-scale ferromagnetic spin-torque devices described above down to individual electron spins in carbon nanotubes and single molecules.  We observe signatures of strong spin-orbit coupling in selected molecules, which may provide an additional all-electrical means of spin manipulation.