Reduction of intrinsic critical current density under a magnetic field along the hard axis of a free layer in a magnetic tunnel junction

Miura, Katsuya*; Sugano, Ryoko*; Ichimura, Masahiko*; Hayakawa, Jun*; Ikeda, Shoji*; Ohno, Hideo*; Maekawa, Sadamichi

We investigated the effect of a magnetic field along a hard in-plane axis on a current-induced magnetization switching in magnetic tunnel junctions. Our recent findings suggest that the effect of mainly appears in the dynamic properties due to the nonconservative force of the spin-transfer torque based on the Slonczewski's model. A simple stability analysis demonstrated that the tilt of the magnetization direction away from the easy axis caused by the presence of induces an imbalance between the spin-transfer and damping torques and that applying a current achieves the further tilted stable state. Achievement of this stable state can be interpreted as the suppression of the effect of the effective demagnetization field. Therefore the major reduction in is due to the suppression of H caused by the presence of .