Adiabatic spin transfer torque induced domain wall (DW) depinning from anotch and DW propagation in a nanowire with a series of notches isinvestigated. Surprisingly, notches help a current to depin a DW and make a DWeasier to propagate along a wire. Following fascinating results on DW dynamicsare found. 1) The depinning current density of a DW in a notch is substantiallylower than the intrinsic threshold value below which a sustainable DWpropagation doesn't exist in a homogeneous wire. 2) The DW displacement from anotch is insensitive to notch geometry and current density when it is betweenthe depinning and the intrinsic threshold current density. 3) A current densitybelow the intrinsic threshold value can induce a sustainable DW propagationalong notched nanowires. These findings not only reveal interesting andcomplicated interaction between a current and a DW, but also have profoundimplications in our current understanding of current-driven DW dynamics as wellas in the design of spintronic devices.
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