The mechanism of depinning process of vortex domain wall (DW) in a planar magnetic nanowire with an asymmetric notch is investigated by using focused magneto-optical Kerr effect (MOKE) magnetometer and micromagnetic modeling. Two distinct depinning fields are directly observed by the single-shot MOKE measurements. Micromagnetic modeling provides physical insight into the details of how the depinning process develops at the asymmetric notch and reveals that the different depinning fields originate from the different chiralities of the vortex DWs.
Bibliographical noteFunding Information:
This work was supported by China Scholarship Council (File No. 2008610077), Natural Science Foundation of China (Grant Nos. 11074046, 51171047, and 61078030), the National Basic Research Program of China (2009CB929201), and. B. Ma and Y. Liu thank for the support from the NSFC (Grant Nos. 51071046, 11174056, and 10974142). We acknowledge the use of facilities in Joel NanoCenter, University of York for high resolution of SEM and e-beam lithography.