Averaged equation for energy diffusion on a graph reveals bifurcation diagram and thermally assisted reversal times in spin-torque driven nanomagnets
arXiv:1210.6253 · doi:10.1063/1.4804070
Abstract
Driving nanomagnets by spin-polarized currents offers exciting prospects in magnetoelectronics, but the response of the magnets to such currents remains poorly understood. We show that an averaged equation describing the diffusion of energy on a graph captures the low-damping dynamics of these systems. From this equation we obtain the bifurcation diagram of the magnets, including the critical currents to induce stable precessional states and magnetization switching, as well as the mean times of thermally assisted magnetization reversal in situations where the standard reaction rate theory of Kramers is no longer valid. These results match experimental observations and give a theoretical basis for a Néel-Brown-type formula with an effective energy barrier for the reversal times.
13 pages, 5 figures
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Cited by in corpus (19)
- Thermally-Assisted Spin-Transfer Torque Dynamics in Energy Space
- Magnetization reversal condition for a nanomagnet within a rotating magnetic field
- Spin Torque Oscillators with Thermal Noise: A Constant Energy Orbit Approach
- Instability analysis of spin torque oscillator with an in-plane magnetized free layer and a perpendicularly magnetized pinned layer
- Magnetization switching by current and microwaves
- Nonlinear analysis of magnetization dynamics excited by spin Hall effect
- Relaxation time and critical slowing down of a spin-torque oscillator
- Dynamic coupling of ferromagnets via spin Hall magnetoresistance
- Switching induced by spin Hall effect in an in-plane magnetized ferromagnet with the easy axis parallel to the current
- Stable oscillation in spin torque oscillator excited by a small in-plane magnetic field
- Metastability of the Nonlinear Wave Equation: Insights from Transition State Theory
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- Switching time of spin-torque-driven magnetization in biaxial ferromagnets