Study of spin valves with L10-FePt pinning layer and different pinned layers

Hui Zhao; Xuan Li; Zongzhi Zhang; Bin Ma; Q. Y. Jin

doi:10.1109/TMAG.2007.892175

Study of spin valves with L1₀-FePt pinning layer and different pinned layers

Hui Zhao, Xuan Li, Zongzhi Zhang, Bin Ma, Q. Y. Jin

Electrical and Computer Engineering

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

5 Scopus citations

Abstract

L1₀ FePt pinned spin valves (SVs) with different pinning/pinned layers: FePt/CoFe, FePt/Ru/CoFe, and FePt/CoFe/Ru/CoFe, were fabricated and investigated. Samples with rigidly ferromagnetic coupled bilayer of FePt (6.0 nm)/CoFe (4.0 nm) show giant magnetore-sistance (GMR) ratio up to 7.06%, which is similar to that in the conventional Mnlr-based SVs. Whereas the free layer coercivity (H_cf) of CoFe (3.0 nm)/NiFe (4.0 nm) is as high as 45 Oe. This is mainly due to the exchange coupling between the free layer and (111) textured FePt layer. Synthetic antiferromagntic structures, FePt/Ru/CoFe and FePt/CoFe/Ru/CoFe, were proved to be very effective in reducing the H _cf value by forming a closed flux pathway in the bottom electrode. Compared with FePt/Ru/CoFe SVs, the FePt/CoFe/Ru/CoFe ones show higher pinned layer switching field. The optimized SV structure in this study is glass/FePt (6.0)/CoFe (2.0)/Ru (0.8)/CoFe (2.5)/Cu (2.4)/CoFe (3.0)/NiFe (4.0)/Pt (2.0) (in unit of nm), which exhibits a GMR ratio of 7.04%, a free layer H_cf of 22 Oe, and a pinned layer switching field of 1824 Oe.

Original language	English (US)
Pages (from-to)	2839-2841
Number of pages	3
Journal	IEEE Transactions on Magnetics
Volume	43
Issue number	6
DOIs	https://doi.org/10.1109/TMAG.2007.892175
State	Published - Jun 2007

Bibliographical note

Funding Information:
This work was supported by the National Nature Science Foundation of China under Grants 10604016, 10374019, 60678008, and 60490290, and the Science and Technology Committee of Shanghai under Grants 05PJ14016 and 06DJ14007.

Keywords

Giant magnetoresistance
L1 FePt
Spin valve
Synthetic antiferromagntic coupling

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title = "Study of spin valves with L10-FePt pinning layer and different pinned layers",

abstract = "L10 FePt pinned spin valves (SVs) with different pinning/pinned layers: FePt/CoFe, FePt/Ru/CoFe, and FePt/CoFe/Ru/CoFe, were fabricated and investigated. Samples with rigidly ferromagnetic coupled bilayer of FePt (6.0 nm)/CoFe (4.0 nm) show giant magnetore-sistance (GMR) ratio up to 7.06%, which is similar to that in the conventional Mnlr-based SVs. Whereas the free layer coercivity (Hcf) of CoFe (3.0 nm)/NiFe (4.0 nm) is as high as 45 Oe. This is mainly due to the exchange coupling between the free layer and (111) textured FePt layer. Synthetic antiferromagntic structures, FePt/Ru/CoFe and FePt/CoFe/Ru/CoFe, were proved to be very effective in reducing the H cf value by forming a closed flux pathway in the bottom electrode. Compared with FePt/Ru/CoFe SVs, the FePt/CoFe/Ru/CoFe ones show higher pinned layer switching field. The optimized SV structure in this study is glass/FePt (6.0)/CoFe (2.0)/Ru (0.8)/CoFe (2.5)/Cu (2.4)/CoFe (3.0)/NiFe (4.0)/Pt (2.0) (in unit of nm), which exhibits a GMR ratio of 7.04%, a free layer Hcf of 22 Oe, and a pinned layer switching field of 1824 Oe.",

keywords = "Giant magnetoresistance, L1 FePt, Spin valve, Synthetic antiferromagntic coupling",

author = "Hui Zhao and Xuan Li and Zongzhi Zhang and Bin Ma and Jin, {Q. Y.}",

note = "Funding Information: This work was supported by the National Nature Science Foundation of China under Grants 10604016, 10374019, 60678008, and 60490290, and the Science and Technology Committee of Shanghai under Grants 05PJ14016 and 06DJ14007.",

year = "2007",

month = jun,

doi = "10.1109/TMAG.2007.892175",

language = "English (US)",

volume = "43",

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T1 - Study of spin valves with L10-FePt pinning layer and different pinned layers

AU - Zhao, Hui

AU - Li, Xuan

AU - Zhang, Zongzhi

AU - Ma, Bin

AU - Jin, Q. Y.

N1 - Funding Information: This work was supported by the National Nature Science Foundation of China under Grants 10604016, 10374019, 60678008, and 60490290, and the Science and Technology Committee of Shanghai under Grants 05PJ14016 and 06DJ14007.

PY - 2007/6

Y1 - 2007/6

N2 - L10 FePt pinned spin valves (SVs) with different pinning/pinned layers: FePt/CoFe, FePt/Ru/CoFe, and FePt/CoFe/Ru/CoFe, were fabricated and investigated. Samples with rigidly ferromagnetic coupled bilayer of FePt (6.0 nm)/CoFe (4.0 nm) show giant magnetore-sistance (GMR) ratio up to 7.06%, which is similar to that in the conventional Mnlr-based SVs. Whereas the free layer coercivity (Hcf) of CoFe (3.0 nm)/NiFe (4.0 nm) is as high as 45 Oe. This is mainly due to the exchange coupling between the free layer and (111) textured FePt layer. Synthetic antiferromagntic structures, FePt/Ru/CoFe and FePt/CoFe/Ru/CoFe, were proved to be very effective in reducing the H cf value by forming a closed flux pathway in the bottom electrode. Compared with FePt/Ru/CoFe SVs, the FePt/CoFe/Ru/CoFe ones show higher pinned layer switching field. The optimized SV structure in this study is glass/FePt (6.0)/CoFe (2.0)/Ru (0.8)/CoFe (2.5)/Cu (2.4)/CoFe (3.0)/NiFe (4.0)/Pt (2.0) (in unit of nm), which exhibits a GMR ratio of 7.04%, a free layer Hcf of 22 Oe, and a pinned layer switching field of 1824 Oe.

AB - L10 FePt pinned spin valves (SVs) with different pinning/pinned layers: FePt/CoFe, FePt/Ru/CoFe, and FePt/CoFe/Ru/CoFe, were fabricated and investigated. Samples with rigidly ferromagnetic coupled bilayer of FePt (6.0 nm)/CoFe (4.0 nm) show giant magnetore-sistance (GMR) ratio up to 7.06%, which is similar to that in the conventional Mnlr-based SVs. Whereas the free layer coercivity (Hcf) of CoFe (3.0 nm)/NiFe (4.0 nm) is as high as 45 Oe. This is mainly due to the exchange coupling between the free layer and (111) textured FePt layer. Synthetic antiferromagntic structures, FePt/Ru/CoFe and FePt/CoFe/Ru/CoFe, were proved to be very effective in reducing the H cf value by forming a closed flux pathway in the bottom electrode. Compared with FePt/Ru/CoFe SVs, the FePt/CoFe/Ru/CoFe ones show higher pinned layer switching field. The optimized SV structure in this study is glass/FePt (6.0)/CoFe (2.0)/Ru (0.8)/CoFe (2.5)/Cu (2.4)/CoFe (3.0)/NiFe (4.0)/Pt (2.0) (in unit of nm), which exhibits a GMR ratio of 7.04%, a free layer Hcf of 22 Oe, and a pinned layer switching field of 1824 Oe.

KW - Giant magnetoresistance

KW - L1 FePt

KW - Spin valve

KW - Synthetic antiferromagntic coupling

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