Reduction of writing field distribution in a magnetic random access memory with toggle switching

Shunsuke Fukami; Hiroaki Honjo; Tetsuhiro Suzuki; Nobuyuki Ishiwata

doi:10.1109/TMAG.2007.900573

Reduction of writing field distribution in a magnetic random access memory with toggle switching

Shunsuke Fukami, Hiroaki Honjo, Tetsuhiro Suzuki, Nobuyuki Ishiwata

NEC Corporation

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

1 Citation (Scopus)

Abstract

We have investigated the distribution of the flop field, which represents writing field in a toggle magnetic random access memory (MRAM). We analyzed the factors of the distribution by dividing them into the 45° and 135° directions in (H_x, H_y) coordinates. We found that the distribution in the 135° direction is mainly caused by stress-induced anisotropy and can be effectively suppressed by adopting materials that maintain low magnetostriction even after the fabrication process. On the other hand, we found that the distribution in the 45° direction depends on the texture and atomic structure of the ferromagnetic layers, and that low distribution can be attained when the ferromagnetic layers are constructed from small crystalline grains or amorphous materials. We demonstrated a toggle MRAM with a distribution of the flop field only half that of the previously reported magnetic tunnel junction stack structure.

Original language	English
Pages (from-to)	3512-3516
Number of pages	5
Journal	IEEE Transactions on Magnetics
Volume	43
Issue number	8
DOIs	https://doi.org/10.1109/TMAG.2007.900573
Publication status	Published - 2007 Aug

Keywords

Anisotropy field
Distribution
Flop field
Magnetic random access memory (MRAM)
Toggle

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10.1109/TMAG.2007.900573

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title = "Reduction of writing field distribution in a magnetic random access memory with toggle switching",

abstract = "We have investigated the distribution of the flop field, which represents writing field in a toggle magnetic random access memory (MRAM). We analyzed the factors of the distribution by dividing them into the 45° and 135° directions in (Hx, Hy) coordinates. We found that the distribution in the 135° direction is mainly caused by stress-induced anisotropy and can be effectively suppressed by adopting materials that maintain low magnetostriction even after the fabrication process. On the other hand, we found that the distribution in the 45° direction depends on the texture and atomic structure of the ferromagnetic layers, and that low distribution can be attained when the ferromagnetic layers are constructed from small crystalline grains or amorphous materials. We demonstrated a toggle MRAM with a distribution of the flop field only half that of the previously reported magnetic tunnel junction stack structure.",

keywords = "Anisotropy field, Distribution, Flop field, Magnetic random access memory (MRAM), Toggle",

author = "Shunsuke Fukami and Hiroaki Honjo and Tetsuhiro Suzuki and Nobuyuki Ishiwata",

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T1 - Reduction of writing field distribution in a magnetic random access memory with toggle switching

AU - Fukami, Shunsuke

AU - Honjo, Hiroaki

AU - Suzuki, Tetsuhiro

AU - Ishiwata, Nobuyuki

PY - 2007/8

Y1 - 2007/8

N2 - We have investigated the distribution of the flop field, which represents writing field in a toggle magnetic random access memory (MRAM). We analyzed the factors of the distribution by dividing them into the 45° and 135° directions in (Hx, Hy) coordinates. We found that the distribution in the 135° direction is mainly caused by stress-induced anisotropy and can be effectively suppressed by adopting materials that maintain low magnetostriction even after the fabrication process. On the other hand, we found that the distribution in the 45° direction depends on the texture and atomic structure of the ferromagnetic layers, and that low distribution can be attained when the ferromagnetic layers are constructed from small crystalline grains or amorphous materials. We demonstrated a toggle MRAM with a distribution of the flop field only half that of the previously reported magnetic tunnel junction stack structure.

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KW - Anisotropy field

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KW - Flop field

KW - Magnetic random access memory (MRAM)

KW - Toggle

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Reduction of writing field distribution in a magnetic random access memory with toggle switching

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