Lattice-matched magnetic tunnel junctions using a Heusler alloy Co2FeAl and a cation-disorder spinel Mg-Al-O barrier

Thomas Scheike, Hiroaki Sukegawa, Takao Furubayashi, Zhenchao Wen, Koichiro Inomata, Tadakatsu Ohkubo, Kazuhiro Hono, Seiji Mitani

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21 Citations (Scopus)

Abstract

Perfectly lattice-matched magnetic tunnel junctions (MTJs) consisting of a Heusler alloy B2-Co2FeAl (CFA) electrode and a cation-disorder spinel (Mg-Al-O) barrier were fabricated by sputtering and plasma oxidation. We achieved a large tunnel magnetoresistance (TMR) ratio of 228% at room temperature (RT) (398% at 5K) for the epitaxial CFA/MgAl-O/CoFe(001) MTJ, in which the effect of lattice defects on TMR ratios is excluded. With inserting a ultrathin (≤1.5 nm) CoFe layer between the CFA and Mg-Al-O, the TMR ratio further increased up to 280% at RT (453% at 5 K), which reflected the importance of controlling barrier-electrode interface states other than the lattice matching.

Original languageEnglish
Article number242407
JournalApplied Physics Letters
Volume105
Issue number24
DOIs
Publication statusPublished - 2014 Dec 15

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Scheike, T., Sukegawa, H., Furubayashi, T., Wen, Z., Inomata, K., Ohkubo, T., Hono, K., & Mitani, S. (2014). Lattice-matched magnetic tunnel junctions using a Heusler alloy Co2FeAl and a cation-disorder spinel Mg-Al-O barrier. Applied Physics Letters, 105(24), [242407]. https://doi.org/10.1063/1.4904716