Spin current generation by spin pumping

Kazuya Ando, Eiji Saitoh

Research output: Chapter in Book/Report/Conference proceedingChapter


Magnetization dynamics is coupled with spin currents by exchanging the spinangular momentum. This coupling allows to control magnetization by spin currents; spin injection into a ferromagnet induces magnetization precession. The inverse of this process, namely, spin current emission from precessing magnetization, is spin pumping, which offers a route for generating spin currents in a wide range of materials. This chapter describes experiments on the generation and detection of spin currents using the spin pumping and inverse spin-Hall effect. The inverse spin-Hall effect, conversion of spin currents into an electric voltage through spin-orbit interaction, induced by the spin pumping was first discovered in a metallic film. The spin pumping in this film is quantitatively consistent with a model calculation based on the Landau-Lifshitz-Gilbert equation. This dynamical spin injection, the spin pumping, offers an easy and versatile way for injecting spin currents into not only metals but also highresistivity materials. In a metal/semiconductor junction, the spin pumping is demonstrated to be controlled electrically through the tuning of dynamical spinexchange coupling at the interface. This spin-injection method works without applying a charge current, which makes it possible to generate spin currents from magnetic insulators; the spin pumping appears even in a metal/insulator junction due to finite spin-exchange interaction at the interface. The spin pumping from an insulator enables nonlinear generation of spin currents: nonlinear spin pumping. The combination of the spin pumping and inverse spin-Hall effect provides an essential route for exploring spin physics in condensed matter.

Original languageEnglish
Title of host publicationHandbook of Spintronics
PublisherSpringer Netherlands
Number of pages24
ISBN (Electronic)9789400768925
ISBN (Print)9789400768918
Publication statusPublished - 2015 Sept 16

ASJC Scopus subject areas

  • General Computer Science
  • General Engineering
  • General Materials Science


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