Tunneling spin polarization and magnetic properties of Co-Fe-B alloys and their dependence on boron content

Takahide Kubota, Tadaomi Daibou, Mikihiko Oogane, Yasuo Ando, Terunobu Miyazaki

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Tunneling spin polarization (TSP) of (Co50Fe50) 100-xBx alloys with various boron contents is measured by superconducting tunneling spectroscopy (STS). Because magnetic tunnel junctions (MTJs) using Co-Fe-B alloys exhibit a large tunnel magnetoresistance (TMR) effect, they are highly valued materials; in addition, the TSP of Co-Fe-B alloys is expected to be high. The maximum observed TSP value is 49% for (Co 50Fe50)80B20, which is higher than that of pure Co50Fe50 (37%). An X-ray diffraction pattern showed that the structure of (Co50Fe50)80B 20 is amorphous. We infer that the structure is changed to the amorphous state by increasing the boron content, which enhances the TSP of Co-Fe-B alloys.

Original languageEnglish
Pages (from-to)L250-L252
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume46
Issue number8-11
DOIs
Publication statusPublished - 2007 Mar 9

Keywords

  • Amorphous ferromagnet
  • Co-Fe-B
  • Superconducting tunneling spectroscopy
  • Tunnel magnetoresistance
  • Tunneling spin polarization

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

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