Spin-polarized currents are able to change the magnetic configuration of nanostructures through the spintransfer effect proposed more than a decade ago. Intensive research is currently directed at understanding the basic physics of this non-equilibrium interaction and designing magnetic nanodevices controlled by electric current. In those devices spin transfer torques play a key role creating dynamic regimes that are not present in conventional magnetic systems. Unfortunately full dynamic study of the phenomenon is not straightforward even for simple spin transfer devices due to the nonlinearity of the Landau-Lifshitz-Gilbert equation governing the magnetization motion. Devices with complicated magnetic anisotropy feature many dynamic regimes: "canted states", multiple precession states, "magnetic fan" regimes, etc. which are often studied by numeric methods. One special case of magnetic anisotropy, a dominating easy plane, turns out to be ubiquitous in experimental designs. This case is characterized by a simplification of the dynamic equations which permits analytical treatment by means of an effective planar equation. The planar equation is presented and discussed for a number of regimes. It is shown how planar description gives an intuitively clear picture of magnetic dynamics and allows to predict new phenomena.

Date Published: 18 August 2009
PDF: 11 pages
Proc. SPIE 7398, Spintronics II, 73980P (18 August 2009); doi: 10.1117/12.826732

Published in SPIE Proceedings Vol. 7398:
Spintronics II
Manijeh Razeghi; Henri-Jean M. Drouhin; Jean-Eric Wegrowe, Editor(s)