Low resistance magnetic tunnel junctions and their interface structures

J. Fujikata, T. Ishi, S. Mori, K. Matsuda, K. Mori, H. Yokota, K. Hayashi, M. Nakada, A. Kamijo, K. Ohashi

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Abstract

Effects of interface structure and oxidation state were studied in stacked magnetic tunnel junction (MTJ) structures with top and bottom antiferromagnetic layers to obtain optimum resistance and high tunneling magnetoresistance (TMR) ratios for read heads. The roughness of the NiFe surface and the Al coverage were significantly improved by introduction of O2 surfactant gas on the Ta-seed-layer surface, which increased TMR ratios of the MTJ with low resistance area (RA) products of less than 10 Ω μm2. Furthermore, it was found that avoidance of Ni oxidation and Co oxidation at the tunnel barrier interface is essential to obtaining high TMR ratios, and that a good Al coverage and Fe-oxide formation may enhance TMR ratios when Fe-rich magnetic materials are used. For the top-type and bottom-type structures, a TMR ratio of 12%-17% with RA products of 6-7 Ω μm2 was obtained, which provides sufficient performance for read heads.

Original languageEnglish
Pages (from-to)7558-7560
Number of pages3
JournalJournal of Applied Physics
Volume89
Issue number11 II
DOIs
Publication statusPublished - 2001 Jun 1
Event8th Joint Magnetism and Magnetic Materials-Intermag Conference - San Antonio, TX, United States
Duration: 2001 Jan 72001 Jan 11

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Fujikata, J., Ishi, T., Mori, S., Matsuda, K., Mori, K., Yokota, H., Hayashi, K., Nakada, M., Kamijo, A., & Ohashi, K. (2001). Low resistance magnetic tunnel junctions and their interface structures. Journal of Applied Physics, 89(11 II), 7558-7560. https://doi.org/10.1063/1.1361054