CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information

K. Miura; S. Ikeda; M. Yamanouchi; H. Yamamoto; K. Mizunuma; H. D. Gan; J. Hayakawa; R. Koizumi; F. Matsukura; H. Ohno

CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information

K. Miura, S. Ikeda, M. Yamanouchi, H. Yamamoto, K. Mizunuma, H. D. Gan, J. Hayakawa, R. Koizumi, F. Matsukura, H. Ohno

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

24 Citations (Scopus)

Abstract

We investigated perpendicular magnetic tunnel junctions (p-MTJs) with a stepped structure for spin-transfer torque random access memory (SPRAM). In conventional p-MTJs, the retention time for storing "1" is shorter than that for storing "0," because of the mangetostatic energy difference between the two states caused by dipole interaction. To counter this, one had to develop materials with low magnetization. Here we show, by employing a stepped structure, that the retention time can be made equivalent regardless of the stored information ("0" or "1"), without resorting to the employed materials. This is because this structure reduces the dipole interlayer coupling between two ferromagnetic layers as the diameter difference of the free and reference layers of MTJ increases.

Original language	English
Title of host publication	2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers
Pages	214-215
Number of pages	2
Publication status	Published - 2011
Event	2011 Symposium on VLSI Technology, VLSIT 2011 - Kyoto, Japan Duration: 2011 Jun 14 → 2011 Jun 16

Publication series

Name	Digest of Technical Papers - Symposium on VLSI Technology
ISSN (Print)	0743-1562

Conference

Conference	2011 Symposium on VLSI Technology, VLSIT 2011
Country/Territory	Japan
City	Kyoto
Period	11/6/14 → 11/6/16

Cite this

Miura, K., Ikeda, S., Yamanouchi, M., Yamamoto, H., Mizunuma, K., Gan, H. D., Hayakawa, J., Koizumi, R., Matsukura, F., & Ohno, H. (2011). CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information. In 2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers (pp. 214-215). Article 5984638 (Digest of Technical Papers - Symposium on VLSI Technology).

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abstract = "We investigated perpendicular magnetic tunnel junctions (p-MTJs) with a stepped structure for spin-transfer torque random access memory (SPRAM). In conventional p-MTJs, the retention time for storing {"}1{"} is shorter than that for storing {"}0,{"} because of the mangetostatic energy difference between the two states caused by dipole interaction. To counter this, one had to develop materials with low magnetization. Here we show, by employing a stepped structure, that the retention time can be made equivalent regardless of the stored information ({"}0{"} or {"}1{"}), without resorting to the employed materials. This is because this structure reduces the dipole interlayer coupling between two ferromagnetic layers as the diameter difference of the free and reference layers of MTJ increases.",

author = "K. Miura and S. Ikeda and M. Yamanouchi and H. Yamamoto and K. Mizunuma and Gan, {H. D.} and J. Hayakawa and R. Koizumi and F. Matsukura and H. Ohno",

year = "2011",

language = "English",

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series = "Digest of Technical Papers - Symposium on VLSI Technology",

pages = "214--215",

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note = "2011 Symposium on VLSI Technology, VLSIT 2011 ; Conference date: 14-06-2011 Through 16-06-2011",

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Miura, K, Ikeda, S, Yamanouchi, M, Yamamoto, H, Mizunuma, K, Gan, HD, Hayakawa, J, Koizumi, R, Matsukura, F & Ohno, H 2011, CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information. in 2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers., 5984638, Digest of Technical Papers - Symposium on VLSI Technology, pp. 214-215, 2011 Symposium on VLSI Technology, VLSIT 2011, Kyoto, Japan, 11/6/14.

CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information. / Miura, K.; Ikeda, S.; Yamanouchi, M. et al.
2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers. 2011. p. 214-215 5984638 (Digest of Technical Papers - Symposium on VLSI Technology).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - Ikeda, S.

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AU - Yamamoto, H.

AU - Mizunuma, K.

AU - Gan, H. D.

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AU - Koizumi, R.

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AB - We investigated perpendicular magnetic tunnel junctions (p-MTJs) with a stepped structure for spin-transfer torque random access memory (SPRAM). In conventional p-MTJs, the retention time for storing "1" is shorter than that for storing "0," because of the mangetostatic energy difference between the two states caused by dipole interaction. To counter this, one had to develop materials with low magnetization. Here we show, by employing a stepped structure, that the retention time can be made equivalent regardless of the stored information ("0" or "1"), without resorting to the employed materials. This is because this structure reduces the dipole interlayer coupling between two ferromagnetic layers as the diameter difference of the free and reference layers of MTJ increases.

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Miura K, Ikeda S, Yamanouchi M, Yamamoto H, Mizunuma K, Gan HD et al. CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information. In 2011 Symposium on VLSI Technology, VLSIT 2011 - Digest of Technical Papers. 2011. p. 214-215. 5984638. (Digest of Technical Papers - Symposium on VLSI Technology).

CoFeB/MgO based perpendicular magnetic tunnel junctions with stepped structure for symmetrizing different retention times of "0" and "1" information

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