Performance of synthetic antiferromagnetic racetrack memory: domain wall versus skyrmion

Abstract
A storage scheme based on racetrack memory, where the information can be coded in a domain or a skyrmion, seems to be an alternative to conventional hard disk drive for high density storage. Here, we perform a full micromagnetic study of the performance of synthetic antiferromagnetic (SAF) racetrack memory in terms of velocity and sensitivity to defects by using experimental parameters. We find that, to stabilize a SAF skyrmion, the Dzyaloshinskii–Moriya interaction in the top and the bottom ferromagnet should have an opposite sign. The velocity of SAF skyrmions and SAF Néel domain walls are of the same order and can reach values larger than 1200 m s−1 if a spin–orbit torque from the spin-Hall effect with opposite sign is applied to both ferromagnets. The presence of disordered anisotropy in the form of randomly distributed grains introduces a threshold current for both SAF skyrmions and SAF domain walls motions.

Citation
Tomasello R, Puliafito V, Martinez E, Manchon A, Ricci M, et al. (2017) Performance of synthetic antiferromagnetic racetrack memory: domain wall versus skyrmion. Journal of Physics D: Applied Physics 50: 325302. Available: http://dx.doi.org/10.1088/1361-6463/aa7a98.

Acknowledgements
The authors acknowledge the executive programme of scientific and technological cooperation between Italy and China for the years 2016–2018 (code CN16GR09) title 'Nanoscale broadband spin-transfer-torque microwave detector' funded by Ministero degli Affari Esteri e della Cooperazione Internazionale. RT and MR also acknowledge Fondazione Carit—Projects—'Sistemi Phased-Array Ultrasonori', and 'Sensori Spintronici'. The work by EM was supported by project WALL, FP7-PEOPLE-2013-ITN 608031 from European Commission, project MAT2014-52477-C5-4-P from Spanish government, and project SA282U14 from Junta de Castilla y Leon. AM acknowledges support from the King Abdullah University of Science and Technology (KAUST). The authors acknowledge André Thiaville for very useful discussions.

Publisher
IOP Publishing

Journal
Journal of Physics D: Applied Physics

DOI
10.1088/1361-6463/aa7a98

arXiv
1610.00894

Additional Links
http://iopscience.iop.org/article/10.1088/1361-6463/aa7a98/meta

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