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Proceedings Paper

Enhancement of spin pumping damping in ferromagnet/CoPt structures (Conference Presentation)
Author(s): Paul Omelchenko

Paper Abstract

Spin-pumping is the phenomenon by which a pure spin current can be injected into a non-magnetic metal from an adjacent ferromagnet. Spin-pumping into Pt is of great interest since Pt exhibits large inverse spin Hall effect. However, Pt limits the efficiency of spin-pumping due to spin-memory loss at the ferromagnet/Pt interface. By alloying Pt with Co we saw a large enhancement in magnetic damping suggesting a significant increase in spin-pumping efficiency. Analyzing the damping results of ferromagnet/CoPt using spin-pumping model yields to an increase in the spin-mixing parameter by a factor of 4 as compared to ferromagnet/Pt. The enhancement in damping cannot be explained by an increase in the interface spin-memory effect since the spin-diffusion length in CoPt is increased by a factor of 2 as compared to pure Pt. An additional potential source of spin-pumping-like interface damping could be originating form the proximity effect. It is found that proximity effect at the ferromagnet/CoPt interface induces a long-range magnetic moment in CoPt, up to 6nm. Proximity effect can also lead to an increase in fluctuating moment in CoPt, which can then enhance the transfer of magnetic momentum from the ferromagnet to CoPt. In this case, effective spin-pumping parameter will depend on the interaction of spin-correlated clusters in CoPt with the adjacent ferromagnet. This is different from the typically used spin-pumping model where the loss of magnetic moment is mediated by the independent normal-metal electrons reflected at the spin-dependent electron potential at the ferromagnet/normal metal interface.

Paper Details

Date Published: 10 September 2019
Proc. SPIE 11090, Spintronics XII, 110901E (10 September 2019); doi: 10.1117/12.2528567
Show Author Affiliations
Paul Omelchenko, Simon Fraser Univ. (Canada)

Published in SPIE Proceedings Vol. 11090:
Spintronics XII
Henri-Jean M. Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

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