Figure 4

Effects of pulsed currents. (a) Pulsed current measurements for fixed current density and two different pulse durations showing current-driven DW speed measurement method. Short pulse duration, 200 ns, wire remains in the same magnetisation configuration. Long pulse duration, 2000 ns, wire magnetisation is fully switched and 180° DW removed. The pulse current density is 1.2 × 1011 Am−2. (b) Current-driven DW mobility curve for AFM coupling obtained by determining the minimum average pulse duration required to fully remove the 180° DW between the measurement contacts for each current density value. The continuous line is a linear regression fit to the data points for values of v e above the threshold where the DWs are set in motion. Results obtained from FM coupled control samples are shown for comparison.