Giant tunnel magnetoresistance at room temperature for junctions using full-Heusler Co2FeAl0.5Si0.5 electrodes

Nobuki Tezuka, Naomichi Ikeda, Satoshi Sugimoto, Koichiro Inomata

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94 Citations (Scopus)

Abstract

The authors have investigated the tunnel magnetoresistance (TMR) effect of magnetic tunnel junctions (MTJs) with Co2FeAl0.5Si 0.5 full-Heusler electrodes and a MgP barrier in the thickness range of 1.5-2.5 nm. A cross-sectional transmission electron micrograph showed the epitaxial growth of both the upper and lower Co2FeAl 0.5Sin.5 layers and a MgO barrier and some distortion in the MgO barrier after annealing above 400 °C. An exponential dependence of resistance x area product on MgO barrier thickness was observed. TMR ratio was strongly affected by MgO barrier thickness, exhibiting maxima of 220% at room temperature and 390% at 5 K. The latter corresponds to the spin polarization of 0.81. It was also found that the features of this MTJ include a small asymmetry voltage and weak temperature dependence of its TMR ratio.

Original languageEnglish
Pages (from-to)L454-L456
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume46
Issue number17-19
DOIs
Publication statusPublished - 2007 May 11

Keywords

  • CoFeAl Si
  • Full-heusler
  • Magnetic tunnel junction
  • MgO barrier
  • Tunnel magnetoresistance
  • Tunneling spin polarization

ASJC Scopus subject areas

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

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