Direct observation of high velocity current induced domain wall motion
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(a) Image of the structure and schematic setup of the experiment. The direction of the field used to nucleate a DW is shown. The sample (1000 nm wide and 40 nm thick Permalloy curved wire) is contacted to a diode. A laser pulse is focused on the diode and the created charge carriers are than injected into the wire. The red circle marks the region where the intensity scan in (b) was measured. (b) Intensity of the marked region in (a) vs time delay. During the current pulse the sample potential changes resulting in a decrease in the intensity and this allows us to deduce the pulse shape.
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(a) XPEEM image series of a Py wire containing a VW. The top image shows the configuration after the initialization by a vertical field. The inset in the lower left shows a micromagnetic simulation of a VW to help visualization of the DW structure. The XPEEM images were taken with vertical contrast (see gray scale bar at the right) and the simulation is shown using this contrast. Current pulses were injected between adjacent images (from top to bottom). After five injections, the DW is displaced by , thus about 400 nm on average per current pulse. After the third pulse, the DW transformed to a double VW that continues moving. (b) Contrast profiles measured along the yellow line indicated in (a) showing the displacements (black lines).
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