Domain-Wall Dynamicsin Magnetic Logic Devices

Domain walls propagate very well through magnetic nanowires and have been used to demonstrate a logic scheme in which the two stable magnetization directions in planar nanowires are used as the two Boolean basis states of a logic system. In this case, magnetic domain walls perform the role of a signal transition edge, and information can be spread throughout an interconnected network of nanowires by the propagation of the magnetic domain walls. The performance of such domain-wall logic is dependent on the dynamics of the domain walls within the magnetic nanowire circuits. Here the issues concerning the dynamic behavior of magnetic domain walls in planar nanowires with inplane magnetization are reviewed. The velocity of domain-wall propagation is a key consideration as it relates ultimately to the operational speed of the logic circuit. Theoretical and experimental work on velocity indicates that domain walls can propagate very rapidly (over 1 km/s) when the wire thickness is small (e.g., 5 nm). The propagation of domain walls through the complex-shaped nanowire components that make up a logic circuit is also discussed. These components include corners, interconnects as well as the logic junctions. Finally, for fully functional magnetic logic the need for overlap in the operational field ranges for domain-wall propagation of the individual circuit components is described.