Synthetic ferrimagnet nanowires with very low critical current density for coupled domain wall motion

Lepadatu, S. et al. (2017) Synthetic ferrimagnet nanowires with very low critical current density for coupled domain wall motion. Scientific Reports, 7, 1640. (doi: 10.1038/s41598-017-01748-7) (PMID:28487513) (PMCID:PMC5431626)

Abstract

Domain walls in ferromagnetic nanowires are potential building-blocks of future technologies such as racetrack memories, in which data encoded in the domain walls are transported using spin-polarised currents. However, the development of energy-efficient devices has been hampered by the high current densities needed to initiate domain wall motion. We show here that a remarkable reduction in the critical current density can be achieved for in-plane magnetised coupled domain walls in CoFe/Ru/CoFe synthetic ferrimagnet tracks. The antiferromagnetic exchange coupling between the layers leads to simple Néel wall structures, imaged using photoemission electron and Lorentz transmission electron microscopy, with a width of only ~100 nm. The measured critical current density to set these walls in motion, detected using magnetotransport measurements, is 1.0 × 1011 Am−2, almost an order of magnitude lower than in a ferromagnetically coupled control sample. Theoretical modelling indicates that this is due to nonadiabatic driving of anisotropically coupled walls, a mechanism that can be used to design efficient domain-wall devices.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McGrouther, Dr Damien and McVitie, Professor Stephen and Benitez Romero, Dr Maria Jose
• Authors: Lepadatu, S., Saarikoski, H., Beacham, R., Benitez, M. J., Moore, T. A., Burnell, G., Sugimoto, S., Yesudas, D., Wheeler, M. C., Miguel, J., Dhesi, S. S., McGrouther, D., McVitie, S., Tatara, G., and Marrows, C. H.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Published Online: 09 May 2017
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in Scientific Reports 7(1):1640
• Publisher Policy: Reproduced under a Creative Commons License