Single Domain Wall Propagation in 2D Magnetic Nano-traps Under Field Pulses

Creation and propagation of a single magnetic domain wall in 2D nanotraps with a square injection pad

“…In fact, those DWTs were technically isolated from the continuously evaporated Py film. As mentioned, using this method, re-deposition issues remaining on the surfaces of these patterned DWTs was significantly reduced, as compared to the focussed ion-beam patterning [14,16,18]. Those structures were all patterned in a Si 3 N 4 TEM membrane [19], and creation and propagation processes of DWs were performed with the Fresnel imaging mode of the Glasgow Lorentz TEM (LTEM) with a defocused distance (Δ) of 3.6 mm [12,14].…”

“…As mentioned, using this method, re-deposition issues remaining on the surfaces of these patterned DWTs was significantly reduced, as compared to the focussed ion-beam patterning [14,16,18]. Those structures were all patterned in a Si 3 N 4 TEM membrane [19], and creation and propagation processes of DWs were performed with the Fresnel imaging mode of the Glasgow Lorentz TEM (LTEM) with a defocused distance (Δ) of 3.6 mm [12,14]. In addition, a 10 nm thick Au film was grown on the backside of the TEM Si 3 N 4 membrane in order to reduce the charging effect occurring in the sample fabrication and imaging processes with the electron-beam patterning and TEM image capturing [16].…”

“…With this structure, a DW could be created at the left end of the first NW at which the injection pad acts as a 'DW reservoir', and it also rectifies the created DW moving along the remaining NWs reproducibly when an external magnetic field applies in the left-to-right direction. Some of those DWTs were fabricated using a beam writer, an electron-beam lithography technique-the Vistec VB6 UHR-EWF system with a field emission gun operating in the voltage range of 50-100 kV [14,16]. Using the VB6 allows us to obtain the spatial resolution of around 3 nm.…”

“…Moreover, using these structures with field pulses, a single DW can move more reproducibly as compared to the case of using a continuous field. Therein, a DW could be excited during a short pulse and overcome a potential barrier created by the entire structure [13,14]. To realize such devices in feasible ways, a complete understanding of the DW behaviors with respect to the structural geometry is needed.…”

“…To realize such devices in feasible ways, a complete understanding of the DW behaviors with respect to the structural geometry is needed. As discussed in our previous works, DWTs are our preferable structures that are designed as discrete thin film elements that consist of an NW connected with two wider end sections [11,12,14]. Among various geometries, a geometry which consists of a 200 nm×1000 nm in-plane nanowire and two diamond shapes was often chosen.…”