Spin-torque shot noise in magnetic tunnel junctions.
A spin polarized current may transfer angular momentum to a ferromagnet, resulting in a spin-torque phenomenon. At the same time the shot noise, associated with the current, leads to a nonequilibrium stochastic force acting on the ferromagnet. We derive a stochastic version of the Landau-Lifshitz-Gilbert equation for a magnetization of a "free" ferromagnetic layer in contact with a "fixed" ferromagnet. We solve the corresponding Fokker-Planck equation and show that the nonequilibrium noise yields to a nonmonotonic dependence of the precession spectrum linewidth on the current.
Chudnovskiy
A L
AL
I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstrasse 9, D-20335 Hamburg, Germany.
Swiebodzinski
J
J
Kamenev
A
A