A Comparative Study on Racetrack Memories: Domain Wall vs. Skyrmion

Racetrack memory (RM), a new storage scheme in which information flows along a nanotrack, has been considered as a potential candidate for future high-density storage device instead of the hard disk drive (HDD). The first RM, which was proposed in 2008 by IBM, relies on a train of opposite magnetic domains separated by domain walls (DWs), named DW-RM. Recently, an alternative information carrier, skyrmion, which was discovered in 2009, has been regarded as a promising replacement of DW for RM, named skyrmion-based RM (SK-RM). So, what are the relationship between DW and skyrmion? What are the key differences between DW and skyrmion, or between DW-RM and SK-RM? What benefits could SK-RM bring and what critical challenges need to be addressed before application? In this paper, we intend to answer these questions through a comparative study between DW-RM and SK-RM. This work will provide guidelines, especially, for circuit and architecture researchers on RM.

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