Structural characterizations of Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions by transmission electron microscopy

T. M. Nakatani; Y. K. Takahashi; T. Ishikawa; M. Yamamoto; K. Hono

doi:10.1016/j.jmmm.2009.09.059

Structural characterizations of Co₂MnSi/MgO/Co₂MnSi magnetic tunnel junctions by transmission electron microscopy

T. M. Nakatani, Y. K. Takahashi, T. Ishikawa, M. Yamamoto, K. Hono

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

11 Citations (Scopus)

Abstract

We have investigated the structure of Co₂MnSi/MgO/Co₂MnSi magnetic tunneling junctions with different tunnel magnetoresistance values depending on the in situ annealing temperatures just after the deposition of the upper Co₂MnSi electrodes. The nano-beam diffraction patterns indicated that the degree of order of the upper Co₂MnSi electrode annealed at 550 °C was higher than that of an electrode annealed at 400 °C. Moreover, the degree of the L2₁ order of the upper Co₂MnSi electrode annealed at 550 °C was even lower than that of the lower Co₂MnSi electrode annealed at an almost equal temperature of 600 °C. Atomic-scale observation using a high-angle annular dark-field (HAADF) method distinctly showed the existence of the L2₁-ordered regions in the B2-ordered matrix in the upper Co₂MnSi electrode annealed at 400 °C.

Original language	English
Pages (from-to)	357-361
Number of pages	5
Journal	Journal of Magnetism and Magnetic Materials
Volume	322
Issue number	3
DOIs	https://doi.org/10.1016/j.jmmm.2009.09.059
Publication status	Published - 2010 Feb
Externally published	Yes

Keywords

CoMnSi
HAADF-STEM
Magnetic tunnel junction
Transmission electron microscopy

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

Access to Document

10.1016/j.jmmm.2009.09.059

Cite this

@article{530d2571a8cf402bab94291ddfc76a1e,

title = "Structural characterizations of Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions by transmission electron microscopy",

abstract = "We have investigated the structure of Co2MnSi/MgO/Co2MnSi magnetic tunneling junctions with different tunnel magnetoresistance values depending on the in situ annealing temperatures just after the deposition of the upper Co2MnSi electrodes. The nano-beam diffraction patterns indicated that the degree of order of the upper Co2MnSi electrode annealed at 550 °C was higher than that of an electrode annealed at 400 °C. Moreover, the degree of the L21 order of the upper Co2MnSi electrode annealed at 550 °C was even lower than that of the lower Co2MnSi electrode annealed at an almost equal temperature of 600 °C. Atomic-scale observation using a high-angle annular dark-field (HAADF) method distinctly showed the existence of the L21-ordered regions in the B2-ordered matrix in the upper Co2MnSi electrode annealed at 400 °C.",

keywords = "CoMnSi, HAADF-STEM, Magnetic tunnel junction, Transmission electron microscopy",

author = "Nakatani, {T. M.} and Takahashi, {Y. K.} and T. Ishikawa and M. Yamamoto and K. Hono",

note = "Funding Information: The authors are grateful to FEI Company Japan Ltd. for their cooperation in the HAADF-STEM observations. This work was partly supported by Grants-in-Aid for Scientific Research on Priority Area “Creation and Control of Spin Current” (Grant nos. 19048001 and 19048029), a Grant-in-Aid for Scientific Research (A) (Grant no. 20246054), and the World Premier International Research Center (WPI) Initiative on Materials Nanoarchitectonics, from the MEXT, Japan. One of the authors (T.M.N.) acknowledges the National Institute for Materials Science (NIMS) for the NIMS junior researcher assistantship.",

year = "2010",

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doi = "10.1016/j.jmmm.2009.09.059",

language = "English",

volume = "322",

pages = "357--361",

journal = "Journal of Magnetism and Magnetic Materials",

issn = "0304-8853",

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TY - JOUR

T1 - Structural characterizations of Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions by transmission electron microscopy

AU - Nakatani, T. M.

AU - Takahashi, Y. K.

AU - Ishikawa, T.

AU - Yamamoto, M.

AU - Hono, K.

N1 - Funding Information: The authors are grateful to FEI Company Japan Ltd. for their cooperation in the HAADF-STEM observations. This work was partly supported by Grants-in-Aid for Scientific Research on Priority Area “Creation and Control of Spin Current” (Grant nos. 19048001 and 19048029), a Grant-in-Aid for Scientific Research (A) (Grant no. 20246054), and the World Premier International Research Center (WPI) Initiative on Materials Nanoarchitectonics, from the MEXT, Japan. One of the authors (T.M.N.) acknowledges the National Institute for Materials Science (NIMS) for the NIMS junior researcher assistantship.

PY - 2010/2

Y1 - 2010/2

N2 - We have investigated the structure of Co2MnSi/MgO/Co2MnSi magnetic tunneling junctions with different tunnel magnetoresistance values depending on the in situ annealing temperatures just after the deposition of the upper Co2MnSi electrodes. The nano-beam diffraction patterns indicated that the degree of order of the upper Co2MnSi electrode annealed at 550 °C was higher than that of an electrode annealed at 400 °C. Moreover, the degree of the L21 order of the upper Co2MnSi electrode annealed at 550 °C was even lower than that of the lower Co2MnSi electrode annealed at an almost equal temperature of 600 °C. Atomic-scale observation using a high-angle annular dark-field (HAADF) method distinctly showed the existence of the L21-ordered regions in the B2-ordered matrix in the upper Co2MnSi electrode annealed at 400 °C.

AB - We have investigated the structure of Co2MnSi/MgO/Co2MnSi magnetic tunneling junctions with different tunnel magnetoresistance values depending on the in situ annealing temperatures just after the deposition of the upper Co2MnSi electrodes. The nano-beam diffraction patterns indicated that the degree of order of the upper Co2MnSi electrode annealed at 550 °C was higher than that of an electrode annealed at 400 °C. Moreover, the degree of the L21 order of the upper Co2MnSi electrode annealed at 550 °C was even lower than that of the lower Co2MnSi electrode annealed at an almost equal temperature of 600 °C. Atomic-scale observation using a high-angle annular dark-field (HAADF) method distinctly showed the existence of the L21-ordered regions in the B2-ordered matrix in the upper Co2MnSi electrode annealed at 400 °C.

KW - CoMnSi

KW - HAADF-STEM

KW - Magnetic tunnel junction

KW - Transmission electron microscopy

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