Title:
Modeling of Spin Transfer Torques

Abstract:
Currents in magnetic multilayers are spin polarized 
and can carry enough angular momentum that they can cause 
magnetic reversal and induce stable precession of the 
magnetization in thin magnetic layers.  The flow of spins is 
determined by the spin-dependent transport properties, like 
conductivity, interface resistance, and spin-flip scattering 
in the magnetic multilayer.  When a current-carrying electron 
spin interacts with a magnetic layer, the exchange interaction 
leads to torques between the spin and the magnetization.  The 
torque that results from this interaction can excite the 
magnetization.  The qualitative features of the dynamics that 
result from the current-induced torque are captured by a simple 
approximation that assumes that the magnetization of the layer 
is uniform.  Even greater agreement results when finite 
temperature effects are included and the magnetization is 
allowed to vary throughout the film.  In this talk, I describe 
the results of quantum mechanical calculations of the behavior 
of spins at interfaces, semiclassical calculations of the spin 
currents flowing in devices, and macrospin modeling of the 
magnetization dynamics.