The effect of the static magnetic susceptibility on the spin precession in MgO based magnetic tunnel junction.

We studied the steady state precession of the spins in the magnetic tunnel junctions. In the field range below the spin-flop transition of synthetic antiferromagnetic pinned layer, the precession mode depends upon the current bias polarity. Above the spin-flop transition, however, the spin precession shows symmetric behavior on the current bias. The dominant mechanism of the spin precession changes from the spin transfer torque to thermal excitation at around the spin-flop transition. The enhancement of thermal fluctuation above the spin-flop transition is analyzed in relation to the static magnetic susceptibility. [ABSTRACT FROM AUTHOR]