Dresden 2006 – wissenschaftliches Programm
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SYMS: Magnetic Switching
SYMS 1: Magnetic Switching I
SYMS 1.3: Hauptvortrag
Montag, 27. März 2006, 16:15–16:45, HSZ 04
Current-induced spin-transfer torque and spin dynamics in spin-valve structures — •Jozef Barnas1,2, Martin Gmitra1, Vitaly Dugaev3, and Albert Fert4 — 1Department of Physics, Adam Mickiewicz University, Poznan, Poland — 2Institute of Molecular Physics, Polish Academy of Sciences, Poznan, Poland — 3Instituto Superior Tecnico, Lisbon, Portugal — 4Unite Mixte de Physique CNRS/THALES, Orsay, France
A unified description of the current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) and current-induced magnetic switching (CIMS) in spin-valve structures has been worked out in terms of a macroscopic model. The description is based on the classical spin diffusion equation for the distribution function and on the relevant boundary conditions for the longitudinal and transverse components of the spin current. The description explains experimentally observed correlations between normal/inverse CPP-GMR and normal/inverse CIMS.
Time evolution of the CIMS and spin dynamics due to spin-transfer torque have been analyzed in terms of a macrospin model by solving the relevant Landau-Lifshitz-Gilbert equation. Current-induced transition to steady precessional modes in zero magnetic field has been found in some asymmetrical structures. Conditions for the occurrence of such precessional modes and the relevant phase diagram have also been found.