Suppression of Spin Pumping at Metal Interfaces

• Main Authors: Lim, Youngmin, Nepal, Bhuwan, Smith, David A, Wu, Shuang, Srivastava, Abhishek, Nakarmi, Prabandha, Mewes, Claudia, Jiang, Zijian, Gupta, Adbhut, Viehland, Dwight D, Klewe, Christoph, Shafer, Padraic, Park, In Jun, Mabe, Timothy, Amin, Vivek P, Heremans, Jean J, Mewes, Tim, Emori, Satoru
• Format: Journal Article
• Language: English
• Published: 08-07-2023
• Subjects: Physics - Materials Science; Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.2305.01853

APL Mater. 11, 101121 (2023) An electrically conductive metal typically transmits or absorbs a spin
current. Here, we report on evidence that interfacing two metal thin films can
suppress spin transmission and absorption. We examine spin pumping in
ferromagnet/spacer/ferromagnet heterostructures, in which the spacer --
consisting of metallic Cu and Cr thin films -- separates the ferromagnetic
spin-source and spin-sink layers. The Cu/Cr spacer largely suppresses spin
pumping -- i.e., neither transmitting nor absorbing a significant amount of
spin current -- even though Cu or Cr alone transmits a sizable spin current.
The antiferromagnetism of Cr is not essential for the suppression of spin
pumping, as we observe similar suppression with Cu/V spacers where V is a
nonmagnetic analogue of Cr. We speculate that diverse combinations of
spin-transparent metals may form interfaces that suppress spin pumping,
although the underlying mechanism remains unclear. Our work may stimulate a new
perspective on understanding and engineering spin transport in metallic
multilayers.