Suppression of Walker breakdown in nanowires with periodic holes

Abstract

The application based on current-driven domain wall (DW) motion mainly depends on the effective control of the moving velocity of the DW and its structural stability. In this paper, we show that a single square hole has a certain suppression effect on Walker breakdown (WB), and by introducing periodic square holes and improving the relevant design, a suppression effect on WB can be achieved in a limited time. As a result, the domain wall remains structurally stable while moving at a very high velocity. The size and position of the holes have an important influence on energy dissipation (ΔE) which plays a crucial role in the suppression of WB. We find that the ΔE strongly relies on the hole size (a), and theΔE has a polynomial relationship with the critical distance. When the current density is the critical value of JWB, the square hole size a = 16 nm and the distance between adjacent holes l = 1500 nm, WB can be suppressed perfectly, and the magnetic domain wall can keep moving at high speed for a long time.