Current-driven domain wall motion in heterostructured ferromagnetic nanowires

Abstract

Micromagnetic modeling shows that the placement of non-magnetic conductive pads on a ferromagnetic wire affects the current-induced velocity of a domain wall (DW) in the wire and can act as a DW chirality filter. The pads shunt the current, causing a non-uniform spin current distribution inside the ferromagnetic wire and an Oersted field transverse to the wire. This suppresses Walker breakdown allowing higher current densities to be imposed before breakdown occurs. The transverse Oersted field pins the DW under some regimes of current density and pad geometry, selectively allowing transmission of DWs of only one chirality. V

Manipulating the magnetization direction of transverse domain walls in Permalloy/Ir strips using nanosecond current pulses

“…In particular, in layers having in-plane magnetization, it may influence the configuration of domain walls that are present in the strip, favoring transverse domain walls (TW) with magnetization parallel to the field. The stabilization of one particular TW configuration by a transverse (Oersted) field during current-induced DW motion (CIDM) may delay the onset of domain wall transformations associated to the Walker breakdown [6] up to higher domain wall velocities, as was already shown for field induced motion, both theoretically and experimentally [7,8,9,10,11,12].…”

Magnetization reversal of the transverse domain wall confined between two clusters of magnetic impurities in a ferromagnetic planar nanowire

“…These traps correspond to critical points, which can act either as pinning sites (potential wells) or blocking sites (potential barriers). The incorporation of artificial defects into the nanowire has been realized by local variations either of geometry [14,[26][27][28][29] or of the magnetic properties [30][31][32][33][34]. Non-magnetic defects like notches patterned as part of the nanowire have been widely used as traps for domain walls.…”

Transition of domain walls induced by current in defect permalloy nanowires

“…Several studies were conducted on geometry, where magnetic field and electric current were applied along the nanowire [5][6][7]. The intrinsic mechanism for the motion of domain wall under magnetic field and electric current has also been discussed in different nanostructures, including nanowires, nanotubes and nanocylinders [8][9][10].…”