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

doi:10.1063/1.1361054

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

^*Corresponding author for this work

Research output: Contribution to journal › Conference article › peer-review

16 Citations (Scopus)

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 language	English
Pages (from-to)	7558-7560
Number of pages	3
Journal	Journal of Applied Physics
Volume	89
Issue number	11 II
DOIs	https://doi.org/10.1063/1.1361054
Publication status	Published - 2001 Jun 1
Externally published	Yes
Event	8th Joint Magnetism and Magnetic Materials-Intermag Conference - San Antonio, TX, United States Duration: 2001 Jan 7 → 2001 Jan 11

ASJC Scopus subject areas

Physics and Astronomy(all)

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title = "Low resistance magnetic tunnel junctions and their interface structures",

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.",

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

year = "2001",

month = jun,

day = "1",

doi = "10.1063/1.1361054",

language = "English",

volume = "89",

pages = "7558--7560",

journal = "Journal of Applied Physics",

issn = "0021-8979",

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note = "8th Joint Magnetism and Magnetic Materials-Intermag Conference ; Conference date: 07-01-2001 Through 11-01-2001",

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TY - JOUR

T1 - Low resistance magnetic tunnel junctions and their interface structures

AU - Fujikata, J.

AU - Ishi, T.

AU - Mori, S.

AU - Matsuda, K.

AU - Mori, K.

AU - Yokota, H.

AU - Hayashi, K.

AU - Nakada, M.

AU - Kamijo, A.

AU - Ohashi, K.

PY - 2001/6/1

Y1 - 2001/6/1

N2 - 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.

AB - 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.

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DO - 10.1063/1.1361054

M3 - Conference article

AN - SCOPUS:0035356674

SN - 0021-8979

VL - 89

SP - 7558

EP - 7560

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 11 II

T2 - 8th Joint Magnetism and Magnetic Materials-Intermag Conference

Y2 - 7 January 2001 through 11 January 2001

ER -

Low resistance magnetic tunnel junctions and their interface structures

Abstract

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