Tunneling spectra of sputter-deposited CoFeB/MgO/CoFeB magnetic tunnel junctions showing giant tunneling magnetoresistance effect

Rie Matsumoto, Yusuke Hamada, Masaki Mizuguchi, Masashi Shiraishi, Hiroki Maehara, Koji Tsunekawa, David D. Djayaprawira, Naoki Watanabe, Yoshinari Kurosaki, Taro Nagahama, Akio Fukushima, Hitoshi Kubota, Shinji Yuasa, Yoshishige Suzuki

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

We measured differential tunneling conductance (dI/dV, d 2I/dV2) spectra of spin-valve-type magnetic tunnel junctions (MTJs) with a MgO(001) tunnel barrier layer and amorphous CoFeB ferromagnetic electrodes that show 315% magnetoresistance (MR) ratio at 4.3 K. The dI/dV spectra showed clear reduction in the conductance at around ±400 mV for a parallel magnetic configuration. Such anomalous spectra have never been observed for MTJs with an amorphous Al-O barrier. The d 2I/dV2 spectra showed several distinct peaks between 5 and 100 mV. Magnon excitations are assigned to an origin of those peaks and thought to be a dominant process to reduce MR at finite bias voltage.

Original languageEnglish
Pages (from-to)611-615
Number of pages5
JournalSolid State Communications
Volume136
Issue number11-12
DOIs
Publication statusPublished - 2005 Dec 1
Externally publishedYes

Keywords

  • A. Magnetic films and multilayers
  • D. Electronic band structure
  • D. Electronic transport
  • D. Tunneling

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry

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    Matsumoto, R., Hamada, Y., Mizuguchi, M., Shiraishi, M., Maehara, H., Tsunekawa, K., Djayaprawira, D. D., Watanabe, N., Kurosaki, Y., Nagahama, T., Fukushima, A., Kubota, H., Yuasa, S., & Suzuki, Y. (2005). Tunneling spectra of sputter-deposited CoFeB/MgO/CoFeB magnetic tunnel junctions showing giant tunneling magnetoresistance effect. Solid State Communications, 136(11-12), 611-615. https://doi.org/10.1016/j.ssc.2005.08.032