Transforming domain motion for 3D racetrack memory with perpendicular magnetic anisotropy

Abstract

Domain-wall motion type magnetic memories are expected to be among the next generation of magnetic recording devices and vertical-NAND (V-NAND) memories. In particular, three-dimensional race track memory (3D-RM) which extends vertically from a substrate is important for high integration. We propose a vertical 3D-RM loop consisting of two horizontal and two vertical nanowires in which the magnetic anisotropy is perpendicular to the substrate. The horizontal nanowires contain perpendicularly magnetized domains and Néel type domain walls (DW). The vertical nanowires contain longitudinally magnetized domains with head-to-head or tail-to-tail domain walls. Domain wall motion is demonstrated using micromagnetic simulations based on the Landau–Lifshitz–Gilbert (LLG) equation. We find that a DW can pass around a corner while deforming its own shape. The threshold current density to push a DW around a corner has maximum value for a wire thickness of about 10 nm.