Spin-torque shot noise in magnetic tunnel junctions

Alexander Chudnovskiy

Hamburg University, 1. Institute for Theoretical Physics, Hamburg, Germany

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 non-equilibrium stochastic force acting on the ferromagnet. We derive stochastic version of 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 non-equilibrium noise yields to a non-monotonous dependence of the precession spectrum linewidth on the current.

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