Thermal Activation Barriers for Creation and Annihilation of Magnetic Droplet Solitons in the Presence of Spin Transfer Torque
arXiv:2005.03416 · doi:10.1103/PhysRevB.101.184421
Abstract
We study noise-induced creation and annihilation of magnetic droplet solitons in experimental parameter regions in which they are linearly stable against drift. Exploiting the rotational symmetry of the problem, we transform to the reference frame rotating with the droplet soliton and introduce an effective potential energy that accounts for the work done against spin-transfer torque to rotate the magnetization between two different orientations. We use this function to compute the activation barrier in both directions between the uniform magnetization state and the droplet soliton state for a variety of nanocontact radii and currents. We investigate droplet soliton structures with both zero and nonzero spin-torque asymmetry parameter. Our approach can be applied to estimate activation barriers for dynamical systems where non-gradient terms can be absorbed by changes of reference frames, and suggests a technique applicable to extended systems that may not be uniformly magnetized.
12 figures, 22 pages
References in corpus (11)
- Spin Transfer Torques
- Theory for a dissipative droplet soliton excited by a spin torque nanocontact
- Stable Magnetic Droplet Solitons in Spin Transfer Nanocontacts
- Thermally assisted spin transfer torque switching in synthetic free layers
- Switching speed distribution of spin-torque-induced magnetic reversal
- Parametric Auto-Excitation of Magnetic Droplet Soliton Perimeter Modes
- Curl Forces and the Nonlinear Fokker-Planck Equation
- Magnetic droplet solitons generated by pure spin currents
- Perturbation Theory for Propagating Magnetic Droplet Solitons
- Stochastic ejection of nanocontact droplet solitons via drift instability
- Propagating magnetic droplet solitons as moveable nanoscale spin-wave sources with tunable direction of emission