Manipulating Nanomagnets with Spin-Polarized Currents

When a spin-polarized current interacts with a magnet, it can transfer 
spin angular momentum to the magnet and thereby directly apply a torque.  
This spin-transfer effect can be used to manipulate the magnetic-moment 
direction of small magnets much more efficiently than using magnetic 
fields. I will discuss the microscopic origin of this effect and the 
dynamical consequences for small magnets.  We find, through GHz-scale 
frequency-domain and direct time-domain measurements on single 
nanomagnets, that spin transfer from a DC current can be used either to 
produce magnetic reversal or to excite steady-state precessional dynamics.  
I will summarize progress in the development of applications such as 
non-volatile magnetic memory and frequency-tunable nanoscale oscillators 
for signal processing.