Thermally activated magnetic reversal induced by a spin-polarized current.

We have measured the statistical properties of magnetic reversal in nanomagnets driven by a spin-polarized current. Like reversal induced by a magnetic field, spin-transfer-driven reversal near room temperature exhibits the properties of thermally activated escape over an effective barrier. However, the spin-transfer effect produces qualitatively different behaviors than an applied magnetic field. We discuss an effective current vs field stability diagram. If the current and field are tuned so that their effects oppose one another, the magnet can exhibit telegraph-noise switching.