Spin–orbit torques in normal metal/Nb/ferromagnet heterostructures

Quantifying the spin–orbit torque (SOT) efficiency with changing the layer thickness is crucial for understanding the physical background of SOT. This study investigates the Nb-thickness-dependent SOT efficiency of two types of layered heterostructures: Ta/Nb/CoFeB and Pt/Nb/CoFeB. We find that the...

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Bibliographic Details
Published in:Scientific reports 2021-10, Vol.11 (1), p.21081-21081, Article 21081
Main Authors: Lee, Min Hyeok, Go, Gyungchoon, Kim, Yong Jin, Cha, In Ho, Kim, Gyu Won, Kim, Taehyun, Lee, Kyung-Jin, Kim, Young Keun
Format: Article
Language:English
Subjects:
639/301
639/766
Efficiency
Humanities and Social Sciences
multidisciplinary
Polarity
Science
Science (multidisciplinary)
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Summary:Quantifying the spin–orbit torque (SOT) efficiency with changing the layer thickness is crucial for understanding the physical background of SOT. This study investigates the Nb-thickness-dependent SOT efficiency of two types of layered heterostructures: Ta/Nb/CoFeB and Pt/Nb/CoFeB. We find that the Nb thickness dependence of the SOT efficiency in the two samples is quite different. In the Pt/Nb series, the SOT sign changes according to the thickness variation because Pt and Nb have different spin–orbit coupling signs. We observe the resulting reversal in switching polarity through current-induced SOT switching experiments. However, due to the same spin–orbit coupling signs of Ta and Nb, no such polarity reversal was observed in Ta/Nb series. Further, we extract the spin diffusion length of Nb in each heterostructure. These results provide a systematic understanding of the material- and thickness-dependent SOT characteristics.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-021-99745-4