Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions

Mikihiko Oogane; Jun Nakata; Hitoshi Kubota; Yasuo Ando; Akimasa Sakuma; Terunobu Miyazaki

doi:10.1143/JJAP.44.L760

Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions

Mikihiko Oogane, Jun Nakata, Hitoshi Kubota, Yasuo Ando, Akimasa Sakuma, Terunobu Miyazaki

ENG - Applied Physics

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

8 Citations (Scopus)

Abstract

We investigated the temperature dependence of the tunnel magnetoresistance (TMR) effect in Co-Mn-Al/Al-oxide/Co-Fe tunnel junctions. The junction prepared without exposure to air during deposition showed very large TMR ratios of 65% at 10 K and 40% at room temperature. In contrast, the junction prepared with air exposure before and after Al-oxide layer fabrication showed a maximum TMR ratio of only 40% at a low temperature. Temperature dependences of tunnel conductance of these junctions were analyzed using a simple model that incorporates two contributions: elastic tunneling with decreasing spin polarization as temperature increases and spin-independent hopping tunneling through trap states in Al-oxide tunnel barriers. Results of analyses indicated that air exposure drastically reduced spin polarization and Curie temperature. It also created an inferior insulating layer at the Co-Mn-Al/Al-oxide interface.

Original language	English
Pages (from-to)	L760-L762
Journal	Japanese Journal of Applied Physics
Volume	44
Issue number	24-27
DOIs	https://doi.org/10.1143/JJAP.44.L760
Publication status	Published - 2005 Jun 24

Keywords

Half-metal
Hausler alloy
Spin polarization
Tunnel magnetoreslstance

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title = "Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions",

abstract = "We investigated the temperature dependence of the tunnel magnetoresistance (TMR) effect in Co-Mn-Al/Al-oxide/Co-Fe tunnel junctions. The junction prepared without exposure to air during deposition showed very large TMR ratios of 65% at 10 K and 40% at room temperature. In contrast, the junction prepared with air exposure before and after Al-oxide layer fabrication showed a maximum TMR ratio of only 40% at a low temperature. Temperature dependences of tunnel conductance of these junctions were analyzed using a simple model that incorporates two contributions: elastic tunneling with decreasing spin polarization as temperature increases and spin-independent hopping tunneling through trap states in Al-oxide tunnel barriers. Results of analyses indicated that air exposure drastically reduced spin polarization and Curie temperature. It also created an inferior insulating layer at the Co-Mn-Al/Al-oxide interface.",

keywords = "Half-metal, Hausler alloy, Spin polarization, Tunnel magnetoreslstance",

author = "Mikihiko Oogane and Jun Nakata and Hitoshi Kubota and Yasuo Ando and Akimasa Sakuma and Terunobu Miyazaki",

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TY - JOUR

T1 - Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions

AU - Oogane, Mikihiko

AU - Nakata, Jun

AU - Kubota, Hitoshi

AU - Ando, Yasuo

AU - Sakuma, Akimasa

AU - Miyazaki, Terunobu

PY - 2005/6/24

Y1 - 2005/6/24

N2 - We investigated the temperature dependence of the tunnel magnetoresistance (TMR) effect in Co-Mn-Al/Al-oxide/Co-Fe tunnel junctions. The junction prepared without exposure to air during deposition showed very large TMR ratios of 65% at 10 K and 40% at room temperature. In contrast, the junction prepared with air exposure before and after Al-oxide layer fabrication showed a maximum TMR ratio of only 40% at a low temperature. Temperature dependences of tunnel conductance of these junctions were analyzed using a simple model that incorporates two contributions: elastic tunneling with decreasing spin polarization as temperature increases and spin-independent hopping tunneling through trap states in Al-oxide tunnel barriers. Results of analyses indicated that air exposure drastically reduced spin polarization and Curie temperature. It also created an inferior insulating layer at the Co-Mn-Al/Al-oxide interface.

AB - We investigated the temperature dependence of the tunnel magnetoresistance (TMR) effect in Co-Mn-Al/Al-oxide/Co-Fe tunnel junctions. The junction prepared without exposure to air during deposition showed very large TMR ratios of 65% at 10 K and 40% at room temperature. In contrast, the junction prepared with air exposure before and after Al-oxide layer fabrication showed a maximum TMR ratio of only 40% at a low temperature. Temperature dependences of tunnel conductance of these junctions were analyzed using a simple model that incorporates two contributions: elastic tunneling with decreasing spin polarization as temperature increases and spin-independent hopping tunneling through trap states in Al-oxide tunnel barriers. Results of analyses indicated that air exposure drastically reduced spin polarization and Curie temperature. It also created an inferior insulating layer at the Co-Mn-Al/Al-oxide interface.

KW - Half-metal

KW - Hausler alloy

KW - Spin polarization

KW - Tunnel magnetoreslstance

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JO - Japanese Journal of Applied Physics

JF - Japanese Journal of Applied Physics

IS - 24-27

ER -

Temperature dependence of tunnel magnetoresistance in Co-Mn-Al/Al-oxide/Co-Fe junctions

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Keywords

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