Geometrical Confinement of Vortex Domain Wall in Constricted Magnetic Nanowire With In-Plane Magnetic Anisotropy

The dynamics of the vortex domain wall (VDW) with head-to-head magnetization configuration in the stepped nanowire is investigated by carrying out a micromagnetic simulation. The stepped area is created at the center of the nanowire by shifting one part in the y-direction. This constricted area will help pin the domain wall (DW) by adjusting its depth ( d) and length ( λ) to implement a high information storage memory based on the multi-bit per cell scheme. It is found that the VDW stability type is highly dependent on stepped area geometries ( d and λ). In addition, confined area dimensions have influenced the VDW dynamics in the stepped nanowire, whereas the VDW velocity increases by increasing d and keeping λ as constant. Furthermore, the VDW depinning current density ( J
_d
) is found to increase with increasing d and decreasing λ. J
_d
could be systematically defined as a function of stepped nanowire dimensions such as thickness (th). Also, the depinning behavior through the stepped area depends on the DW magnetization configuration. Whereas VDW with clockwise chirality (CWVDW) and up polarity has a higher depinning current density than CWVDW with down polarity.