Magnetic domain wall (DW) motion along a nanowire underpins many proposals of spintronic devices. High DW propagation velocity is obviously important because it determines device speed. Thus it is interesting to search for effective control knobs of DW dynamics. We report a counter-intuitive finding that notches in an otherwise homogeneous magnetic nanowire can boost current-induced domain wall (DW) propagation. DW motion in notch-modulated wires can be classified into three phases: 1) A DW is pinned around a notch when the current density is below the depinning current density. 2) DW propagation velocity is boosted by notches above the depinning current density and when non-adiabatic spin-transfer torque strength b is smaller than the Gilbert damping constant a. The boost can be manyfold. 3) DW propagation velocity is hindered when b>a.

王向荣，香港科技大学终身教授；1984年毕业于武汉大学物理系，同年通过中美联合招收物理研究生选拨考试(CUSPEA)赴美深造；1990年在美国罗彻斯特大学(University of Rochester)获博士学位；1992受聘于香港科技大学至今。研究方向：凝聚态理论，研究领域包括无规系统中的量子相变，低维系统的电子输运及磁动力学。