Vortex Domain Wall Formation in Nanowires With Twin Pinning Sites

A set of symmetric twin pinning sites of varying distances on Permalloy nanowires of different widths have been investigated and applied in a racetrack memory scenario using micromagnetic simulations. The nanowire width as well as pinning sites distance were found to affect the vortex domain wall formation, while the writing performance is subject to the writing head dimensions and the external field strength. Nanowires with a width of 600 nm and 800 nm with twin pinning sites at a distance of 1 m have been found to favor the formation of the vortex domain wall compared with 400 nm and 1 m nanowires. The detailed micromagnetic simulations show that a pinning site distance of 1 m and a nanowire width of 800 nm are optimal for an information storage device. The results of the write scenario simulations carried out for this device indicate that, for a successful writing process, an applied field length (AFL) of value 1 m and an applied field magnitude (AFM) of -0.05 are most suitable for information writing processes.