School of Physics and Astronomy, E C Stoner Laboratory, University of Leeds, Leeds, UK.
J Phys Condens Matter. 2012 Jan 18;24(2):024210. doi: 10.1088/0953-8984/24/2/024210. Epub 2011 Dec 15.
We have studied the dependence on the domain wall structure of the spin-transfer torque current density threshold for the onset of wall motion in curved, Gd-doped Ni(80)Fe(20) nanowires with no artificial pinning potentials. For single vortex domain walls, for both 10% and 1% Gd-doping concentrations, the threshold current density is inversely proportional to the wire width and significantly lower compared to the threshold current density measured for transverse domain walls. On the other hand for high Gd concentrations and large wire widths, double vortex domain walls are formed which require an increase in the threshold current density compared to single vortex domain walls at the same wire width. We suggest that this is due to the coupling of the vortex cores, which are of opposite chirality, and hence will be acted on by opposing forces arising through the spin-transfer torque effect.
我们研究了在没有人为钉扎势的情况下，自旋转移扭矩电流密度阈值与弯曲的掺钆 Ni(80)Fe(20)纳米线中壁结构的依赖关系，以启动壁运动。对于单涡旋畴壁，对于 10%和 1%的掺钆浓度，阈值电流密度与线宽成反比，并且与测量的横向畴壁的阈值电流密度相比显著降低。另一方面，对于高掺钆浓度和大线宽，形成了双涡旋畴壁，与相同线宽的单涡旋畴壁相比，需要增加阈值电流密度。我们认为这是由于涡旋核的耦合所致，涡旋核的手性相反，因此将受到通过自旋转移扭矩效应产生的相反力的作用。
