We show that a spin-polarized dc current passing through a small magnetic element induces two-state, random telegraph switching of the magnetization via the spin-momentum transfer effect. The resistances of the states differ by up to 50% of the change due to complete magnetization reversal. Fluctuations are seen for a wide range of currents and magnetic fields, with rates that can exceed 2 GHz, and involve collective motion of a large volume (10^4^ nm^3^) of spins. Switching rate trends with field and current indicate that increasing temperature alone cannot explain the dynamics. The rates approach a stochastic regime wherein dynamics are governed by both precessional motion and thermal perturbations.
Citation: Physical Review B (Condensed Matter and Materials Physics)
Pub Type: Journals
1/f noise, spin-momentum transfer, spin-valve, telegraph noise