Dynamics of exchange switching of magnetic junctions

The switching dynamics of a thin free layer of a spin-valve magnetic junction during domination of the injection mechanism of interaction of the spin-polarized current with the magnetic lattice is studied. It is shown that, in the absence of dissipation, there exists an integral of motion, even if current flows through the junction. The trajectory of the precessing magnetization vector below and above the instability threshold is found. A nonstationary solution describing the precession dynamics is obtained. The time of the junction switching in the limiting cases of weak and strong dissipation is estimated.