Domain Wall Configurations and Interactions in Nanowires With Perpendicular Magnetic Anisotropy

Abstract

Magnetic thin film wires with perpendicular magnetic anisotropy (PMA) containing domain walls (DWs) have been proposed for magnetic logic and memory devices. Using micromagnetic simulations, the magnetic configuration of a DW as a function of the magnitude of the PMA, wire width and thickness is described, showing the regimes of stability of Bloch and Néel walls. Stray field leads to repulsive interactions preventing the formation of 360 degree DWs, and promote uniform spacing between multiple DWs confined within a nanowire. Introduction:

Racetrack memory based on in-plane-field controlled domain-wall pinning

“…First, the width of the created anisotropy boundary is 22 nm, but could be further reduced by switching from Ga ions to, for instance, He ions 32 . Secondly, the actual limiting factor is the minimal distance between two domain walls at which they do not interact with each other by dipolar fringe fields, which is considerably more than 22 nm 33 , 34 , just as in a traditional racetrack device. Finally, we note that for the simple anisotropy profile we need to create, a focussed ion beam is not essentially required.…”