Events in Physics
Yaroslaw Bazaliy, University of South Carolina
Qualitative methods for spin transfer dynamics
Yaroslaw Bazaliy, University of South Carolina
This talk will review the spin-transfer effect, discuss its applications for magnetic moment manipulation, and show how one can qualitatively understand and predict the novel dynamic regimes in spin- transfer devices.
Spin-transfer torque is a result of a non-equilibrium magnetic interaction induced by a flow of electrons. In nano-size devices it provides a mechanism for current-induced magnetic switching, which has many potential applications in computer memory and logic. Spin torque is qualitatively different from the familiar torques produced by external magnetic field or magnetic anisotropy. For example, spin- transfer can use the electromotive force of a current source to pump energy into the magnetic system. The resulting dynamic behavior of the magnetic moment is often counter-intuitive and is usually obtained from straightforward but tedious calculations or numeric experiments.
We will discuss two ways of building an intuitive picture of spin- transfer induced dynamics, which allows one to make qualitative predictions about the device's behavior. They are the invariant criteria of equilibrium stability, the condition for destabilization due to equilibrium disappearence [1], and a more restrictive planar approximation [2-4]. These methods will be used to discuss a number of representative experiments.
References
1. Inti Sodemann and Ya. B. Bazaliy, Phys. Rev. B 84, 064422 (2011).
2. Ya. B. Bazaliy, Appl. Phys. Lett. 91, 262510 (2007).
3. Ya. B. Bazaliy, Phys. Rev. B 76, 140402(R) (2007).
4. Ya. B. Bazaliy, arXiv:1109.1331 (2011).