Confinement and Protection of Skyrmions by Patterns of Modified Magnetic Properties

Abstract

Magnetic skyrmions are versatile topological excitations that can be used as nonvolatile information carriers. The confinement of skyrmions in channels is fundamental for any application based on the accumulation and transport of skyrmions. Here, we report a method that allows effective position control of skyrmions in designed channels by engineered energy barriers and wells, which is realized in a magnetic multilayer film by harnessing the boundaries of patterns with modified magnetic properties. We experimentally and computationally demonstrate that skyrmions can be attracted or repelled by the boundaries of areas with modified perpendicular magnetic anisotropy and Dzyaloshinskii–Moriya interaction. By fabricating square and stripe patterns with modified magnetic properties, we show the possibility of building reliable channels for confinement, accumulation, and transport of skyrmions, which effectively protect skyrmions from being destroyed at the device edges. Our results are useful for the design of spintronic applications using either static or dynamic skyrmions.

Local control of magnetic interface effects in chiral Ir|Co|Pt multilayers using Ga+ ion irradiation

“…However, these attributes can usually only be changed for the entire layer or device. The ability to locally control these magnetic parameters could greatly enhance the functionality of skyrmion based devices [25][26][27][28], or devices that use other types of chiral textures. Enabling the creation of regions with high and low energy that could then be used to pin, guide [25][26][27][28], or nucleate [17,29,30] such textures at desired locations in the device.…”

“…The ability to locally control these magnetic parameters could greatly enhance the functionality of skyrmion based devices [25][26][27][28], or devices that use other types of chiral textures. Enabling the creation of regions with high and low energy that could then be used to pin, guide [25][26][27][28], or nucleate [17,29,30] such textures at desired locations in the device. It has already been well established that Ga + and other types of ion irradiation can be used to locally tune the magnetic parameters of single magnetic layers in areas as small as 40 nm [31][32][33][34], but its effect on magnetic multilayers is not yet understood.…”

Particle-like skyrmions interacting with a funnel obstacle

“…Most recently, several experimental reports demonstrated that the perpendicular magnetic anisotropy (PMA) in a magnetic substrate hosting skyrmions could be modified locally in a precise manner [32,33], which could be an effective method for constructing an artificial pinning landscape. The artificial pinning landscape can be used to confine and protect skyrmions [32,33] and, meanwhile, may affect the static and dynamic properties of skyrmions [32][33][34].…”

Confinement of Magnetic Skyrmions to Corrals of Artificial Surface Pits with Complex Geometries

“…By using helium ion beam, the DM interaction in a localized region was modified to confine skyrmions in simple geometric shapes like nano-strips and squares [29]. Recently, it was demonstrated that skyrmions can be effectively confined in channels by fabricating stripes with modified magnetic properties in a single ferromagnetic film [30]. Alternatively, Zhang et al [31] showed that skyrmions were directly created by scanning the surface of a specimen by a magnetic force microscopy (MFM) tip with bias field.…”