Injecting, controlling, and storing magnetic domain walls in ferromagnetic nanowires

Abstract

Domain walls in ferromagnetic nanowires are important for proposed devices in recording, logic, and sensing. The realization of such devices depends in part on the ability to quickly and accurately control the domain wall from creation until placement. Using micromagnetic computer simulation we demonstrate how a combination of externally applied magnetic fields is used to quickly inject, move, and accurately place multiple domain walls within a single wire for potential recording and logical operations. The use of a magnetic field component applied perpendicular to the principle domain wall driving field is found to be critical for increased speed and reliability. The effects of the transverse field on the injection and trapping of the domain wall will be shown to be of particular importance.

Stability of steady states in ferromagnetic rings

“…These solutions are outside the separatrix, since the solutions inside the separatrix take theirs values in intervals which sizes is less than π. These solutions satisfy (16)…”

“…This property plays an important role in numerical data storage since the information is encoded by the localization of DWs (see [2,15,20]). Because of these potential applications, DW dynamics in ferromagnetic wires is intensively investigated as well in Physics (see [16,19,[23][24][25][26][27]) as in Mathematics (see [3,8,10,17,22]). In [12,14,18], DW dynamics and magnetization reversal in ferromagnetic rings are investigated.…”

Application of local transverse fields for domain wall control in ferromagnetic nanowire arrays

“…We have previously demonstrated that the transverse field could be applied longer which would allow domain walls to move more than one notch at a time. 25 The technique of using a locally applied transverse field pulse could also be used in the current driven case. In this situation, a current in a ferromagnetic wire would provide the driving force and the local transverse field could be used to select which domain wall to move, similar to the process shown in Fig.…”

“…[21][22][23][24] The ability of the transverse field to change the domain wall speed also impacts the ability of a notch to trap a domain wall, in that fast moving walls can pass a notch that is capable of trapping a slower moving wall. [25][26][27] When the transverse field component is applied parallel to the direction of the magnetic moments within the domain wall, it will speed up, and if applied anti-parallel, it will slow down. 22 Similarly in Fig.…”