Optimal time-dependent polarized current pattern for fast domain wall propagation in nanowires: Exact solutions for biaxial and uniaxial anisotropies

摘要

One of the important issues in nanomagnetism is to lower the current neededfor a technologically useful domain wall (DW) propagation speed. Based on themodified Landau-Lifshitz-Gilbert (LLG) equation with both Slonczewskispin-transfer torque and the field-like torque, we derive the optimal spincurrent pattern for fast DW propagation along nanowires. Under such conditions,the DW velocity in biaxial wires can be enhanced as much as ten times comparedto the velocities achieved in experiments so far. Moreover, the fast variationof spin polarization can help DW depinning. Possible experimental realizationsare discussed.