No abstract

We show that the application of a spin-polarized current to a double p domain wall system with a variable distance between the walls results in an interaction between the two domain walls. The transmission spectrum changes from that of a spin-dependent resonant double barrier to one like a [Formula: see text] wall. In addition, the spin torque on each individual wall creates coupled motion in the domain walls. The walls move independently with a fast speed at large separations, but slow considerably at small separations.

Charge resistance and spin torque are generated by coherent carrier transport through ferromagnetic 2π domain walls, although they follow qualitatively different trends than for π domain walls. The charge resistance of 2π domain walls reaches a maximum at an intermediate wall thickness, unlike π domain walls, whose resistance decreases monotonically with wall thickness. The peak amplitude of the spin torque and the optimal thickness of the domain wall to maximize torque for a 2π wall are more than twice as large as found for a π domain wall in the same material, producing a larger domain wall velocity for the 2π wall and suggesting unexpected nonlinearities in magnetoelectronic devices incorporating domain wall motion. arXiv:0909.3831v1 [cond-mat.mes-hall]