60% magnetoresistance at room temperature in Co-Fe/Al-O/Co-Fe tunnel junctions oxidized with Kr-O2 plasma

Masakiyo Tsunoda; Kazuhiro Nishikawa; Satoshi Ogata; Migaku Takahashi

doi:10.1063/1.1475363

60% magnetoresistance at room temperature in Co-Fe/Al-O/Co-Fe tunnel junctions oxidized with Kr-O₂ plasma

Masakiyo Tsunoda, Kazuhiro Nishikawa, Satoshi Ogata, Migaku Takahashi

Research Center for Green X-Tech

Tohoku University

Research output: Contribution to journal › Article › peer-review

60 Citations (Scopus)

Abstract

The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta50Å/Cu200Å/Ta200Å/Ni- Fe50Å/Cu50Å/Mn₇₅Ir₂₅100Å/Co ₇₀Fe₃₀25Å/Al-O/Co₇₀Fe ₃₀25Å/Ni-Fe100Å/Cu200Å/Ta50Å. Using Kr-O ₂ plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300°C, while the achieved TMR ratio of the MTJ fabricated with usual Ar-O₂ plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr-O₂ plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.

Original language	English
Pages (from-to)	3135-3137
Number of pages	3
Journal	Applied Physics Letters
Volume	80
Issue number	17
DOIs	https://doi.org/10.1063/1.1475363
Publication status	Published - 2002 Apr 29

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title = "60% magnetoresistance at room temperature in Co-Fe/Al-O/Co-Fe tunnel junctions oxidized with Kr-O2 plasma",

abstract = "The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta50{\AA}/Cu200{\AA}/Ta200{\AA}/Ni- Fe50{\AA}/Cu50{\AA}/Mn75Ir25100{\AA}/Co 70Fe3025{\AA}/Al-O/Co70Fe 3025{\AA}/Ni-Fe100{\AA}/Cu200{\AA}/Ta50{\AA}. Using Kr-O 2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300°C, while the achieved TMR ratio of the MTJ fabricated with usual Ar-O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr-O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.",

author = "Masakiyo Tsunoda and Kazuhiro Nishikawa and Satoshi Ogata and Migaku Takahashi",

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T1 - 60% magnetoresistance at room temperature in Co-Fe/Al-O/Co-Fe tunnel junctions oxidized with Kr-O2 plasma

AU - Tsunoda, Masakiyo

AU - Nishikawa, Kazuhiro

AU - Ogata, Satoshi

AU - Takahashi, Migaku

PY - 2002/4/29

Y1 - 2002/4/29

N2 - The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta50Å/Cu200Å/Ta200Å/Ni- Fe50Å/Cu50Å/Mn75Ir25100Å/Co 70Fe3025Å/Al-O/Co70Fe 3025Å/Ni-Fe100Å/Cu200Å/Ta50Å. Using Kr-O 2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300°C, while the achieved TMR ratio of the MTJ fabricated with usual Ar-O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr-O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.

AB - The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta50Å/Cu200Å/Ta200Å/Ni- Fe50Å/Cu50Å/Mn75Ir25100Å/Co 70Fe3025Å/Al-O/Co70Fe 3025Å/Ni-Fe100Å/Cu200Å/Ta50Å. Using Kr-O 2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300°C, while the achieved TMR ratio of the MTJ fabricated with usual Ar-O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr-O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.

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JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 17

ER -

60% magnetoresistance at room temperature in Co-Fe/Al-O/Co-Fe tunnel junctions oxidized with Kr-O₂ plasma

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