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Jpn. J. Appl. Phys. 44 (2005) pp. L760-L762  |Previous Article| |Next Article|  |Table of Contents|
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Letter

Temperature Dependence of Tunnel Magnetoresistance in Co–Mn–Al/Al–Oxide/Co–Fe Junctions

Mikihiko Oogane, Jun Nakata, Hitoshi Kubota¹, Yasuo Ando, Akimasa Sakuma and Terunobu Miyazaki

Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba-yama 05, Sendai 980-8579, Japan
¹Nanoelectronics Research Institute, AIST, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan

(Received April 13, 2005; accepted April 19, 2005; published June 3, 2005)

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.

URL: http://jjap.jsap.jp/link?JJAP/44/L760/
DOI: 10.1143/JJAP.44.L760
KEYWORDS:Heusler alloy, tunnel magnetoresistance, spin polarization, half-metal

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References | Citing Articles (7)

1. S. Tehrani, B. Engel, J. M. Slaughter, E. Chen, M. DeHerrera, M. Durlam, P. Naji, R. Whig, J. Janesky and J. Calder: IEEE Trans. Magn. 36 (2000) 2752.
2. S. S. P. Parkin, K. P. Roche, M. G. Samant, P. M. Rice, R. B. Beyers, R. E. Scheuerlein, E. J. O'Sullivan, S. L. Brown, J. Bucchigano, D. W. Abraham, Y. Lu, M. Rooks, P. L. Trouilloud, R. A. Wanner and W. J. Gallagher: J. Appl. Phys. 85 (1999) 5828[AIP Scitation].
3. K. Inomata, Y. Saito, K. Nakajima and M. Sagoi: J. Appl. Phys. 87 (2000) 6064[AIP Scitation].
4. Y. S. Song, S. J. Park, T. W. Kim and C. W. Chung: Electrochem. Solid-State Lett. 7 (2004) C64.
5. C. T. Tanaka, J. Nowak and J. S. Moodera: J. Appl. Phys. 86 (1999) 6239[AIP Scitation].
6. S. Ishida, S. Fuji, S. Kashiwagi and S. Asano: J. Phys. Soc. Jpn. 64 (1995) 2152.
7. S. Kammerer, A. Thomas, A. Hutten and G. Reiss: Appl. Phys. Lett. 85 (2004) 79[AIP Scitation].
8. K. Inomata, S. Okamura, R. Goto and N. Tezuka: Jpn. J. Appl. Phys. 42 (2003) L419[JSAP].
9. T. Marukame, T. Kasahara, K. Matsuda, T. Uemura and M. Yamamoto: Jpn. J. Appl. Phys. 44 (2005) L521[JSAP].
10. H. Kubota, J. Nakata, M. Oogane, Y. Ando, A. Sakuma and T. Miyazaki: Jpn. J. Appl. Phys. 43 (2004) L984[JSAP].
11. C. H. Shang, J. Nowak, R. Jansen, and J. S. Moodera: Phys. Rev. B 58 (1998) R2917[APS].
12. R. Stratton: J. Phys. Chem. Solids 23 (1962) 1177[CrossRef].
13. M. Oogane, T. Daibou, H. Kubota, Y. Ando and T. Miyazaki: Trans. Mater. Res. Soc. 29 (2004) 1527.
14. T. Hagler, R. Kinder and G. Bayreuther: J. Appl. Phys. 89 (2001) 7570[AIP Scitation].
15. X. F. Han, M. Oogane, H. Kubota, Y. Ando and T. Miyazaki: Appl. Phys. Lett. 77 (2000) 283[AIP Scitation].

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