Electrically tunable spin injector free from the impedance mismatch problem

K. Ando, S. Takahashi, J. Ieda, H. Kurebayashi, T. Trypiniotis, C. H.W. Barnes, S. Maekawa, E. Saitoh

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Abstract

Injection of spin currents into solids is crucial for exploring spin physics and spintronics. There has been significant progress in recent years in spin injection into high-resistivity materials, for example, semiconductors and organic materials, which uses tunnel barriers to circumvent the impedance mismatch problem; the impedance mismatch between ferromagnetic metals and high-resistivity materials drastically limits the spin-injection efficiency. However, because of this problem, there is no route for spin injection into these materials through low-resistivity interfaces, that is, Ohmic contacts, even though this promises an easy and versatile pathway for spin injection without the need for growing high-quality tunnel barriers. Here we show experimental evidence that spin pumping enables spin injection free from this condition; room-temperature spin injection into GaAs from Ni 81 Fe 19 through an Ohmic contact is demonstrated through dynamical spin exchange. Furthermore, we demonstrate that this exchange can be controlled electrically by applying a bias voltage across a Ni 81 Fe 19/GaAs interface, enabling electric tuning of the spin-pumping efficiency.

Original languageEnglish
Pages (from-to)655-659
Number of pages5
JournalNature Materials
Volume10
Issue number9
DOIs
Publication statusPublished - 2011 Sep

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ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Ando, K., Takahashi, S., Ieda, J., Kurebayashi, H., Trypiniotis, T., Barnes, C. H. W., Maekawa, S., & Saitoh, E. (2011). Electrically tunable spin injector free from the impedance mismatch problem. Nature Materials, 10(9), 655-659. https://doi.org/10.1038/nmat3052