Co-based Heusler alloys for CPP-GMR spin-valves with large magnetoresistive outputs

T. M. Nakatani; N. Hase; H. S. Goripati; Y. K. Takahashi; T. Furubayashi; K. Hono

doi:10.1109/TMAG.2011.2174436

Co-based Heusler alloys for CPP-GMR spin-valves with large magnetoresistive outputs

T. M. Nakatani^*, N. Hase, H. S. Goripati, Y. K. Takahashi, T. Furubayashi, K. Hono

^*Corresponding author for this work

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

39 Citations (Scopus)

Abstract

We studied various Heusler alloy compositions for the ferromagnetic layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valves (SVs) to obtain large MR outputs for the read sensor applications. The exchange biased SV with Co₂ Fe(Al_0.5 Si_0.5 ) alloy showed a resistance change-area product (Δ RA) of 6 mΩ μm ² and an MR ratio of 21% at room temperature when the Co₂ Fe(Al_0.5 Si_0.5 ) layer was well-B2-ordered by a high temperature annealing at 500°C. The critical bias current density for the spin torque effect on the reduction of ΔRA was ∼ 3 × 10 ⁷ A/cm². Based on the high spin polarization directly measured by the point contact Andreev reflection method, Co₂ (Cr _0.1 Fe_0.9 )Si, Co₂ Mn(Ga_0.5 Sn _0.5 ), and Co₂ Fe(Ge_0.5 Ga_0.5 ) alloy thin films were investigated for CPP-GMR SVs. Among them, the Co ₂Fe(Ge_0.5Ga_0.5) alloy showed a high CPP-GMR ratio in the pseudo SVs exceeding 40% at RT and 120% at 10 K.

Original language	English
Article number	6187793
Pages (from-to)	1751-1757
Number of pages	7
Journal	IEEE Transactions on Magnetics
Volume	48
Issue number	5 PART 1
DOIs	https://doi.org/10.1109/TMAG.2011.2174436
Publication status	Published - 2012 May
Externally published	Yes

Keywords

CPP-GMR
Heusler alloy
half-metal
read head

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

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10.1109/TMAG.2011.2174436

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@article{69c7dd9e61ed4b7a9bf9bb95a1047ac4,

title = "Co-based Heusler alloys for CPP-GMR spin-valves with large magnetoresistive outputs",

abstract = "We studied various Heusler alloy compositions for the ferromagnetic layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valves (SVs) to obtain large MR outputs for the read sensor applications. The exchange biased SV with Co2 Fe(Al0.5 Si0.5 ) alloy showed a resistance change-area product (Δ RA) of 6 mΩ μm 2 and an MR ratio of 21% at room temperature when the Co2 Fe(Al0.5 Si0.5 ) layer was well-B2-ordered by a high temperature annealing at 500°C. The critical bias current density for the spin torque effect on the reduction of ΔRA was ∼ 3 × 10 7 A/cm2. Based on the high spin polarization directly measured by the point contact Andreev reflection method, Co2 (Cr 0.1 Fe0.9 )Si, Co2 Mn(Ga0.5 Sn 0.5 ), and Co2 Fe(Ge0.5 Ga0.5 ) alloy thin films were investigated for CPP-GMR SVs. Among them, the Co 2Fe(Ge0.5Ga0.5) alloy showed a high CPP-GMR ratio in the pseudo SVs exceeding 40% at RT and 120% at 10 K.",

keywords = "CPP-GMR, Heusler alloy, half-metal, read head",

author = "Nakatani, {T. M.} and N. Hase and Goripati, {H. S.} and Takahashi, {Y. K.} and T. Furubayashi and K. Hono",

note = "Funding Information: ACKNOWLEDGMENT This work was supported in part by the Grant-in-Aid for Scientific Research (B) and (A) (Grand Nos. 20360322 and 22246091), the Grant-in-Aid for Scientific Research in Priority Area “Creation and control of spin current” (Grant No. 19048029), JST-PREST, and the WPI Initiative on Materials Nanoarchitronics, MEXT, Japan. T. M. Nakatani was supported by the JSPS Research Fellowship for Young Scientists. N. Hase and H. S. Goripati acknowledge NIMS for provisions of the NIMS Junior Research Assistantship.",

year = "2012",

month = may,

doi = "10.1109/TMAG.2011.2174436",

language = "English",

volume = "48",

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T1 - Co-based Heusler alloys for CPP-GMR spin-valves with large magnetoresistive outputs

AU - Nakatani, T. M.

AU - Hase, N.

AU - Goripati, H. S.

AU - Takahashi, Y. K.

AU - Furubayashi, T.

AU - Hono, K.

N1 - Funding Information: ACKNOWLEDGMENT This work was supported in part by the Grant-in-Aid for Scientific Research (B) and (A) (Grand Nos. 20360322 and 22246091), the Grant-in-Aid for Scientific Research in Priority Area “Creation and control of spin current” (Grant No. 19048029), JST-PREST, and the WPI Initiative on Materials Nanoarchitronics, MEXT, Japan. T. M. Nakatani was supported by the JSPS Research Fellowship for Young Scientists. N. Hase and H. S. Goripati acknowledge NIMS for provisions of the NIMS Junior Research Assistantship.

PY - 2012/5

Y1 - 2012/5

N2 - We studied various Heusler alloy compositions for the ferromagnetic layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valves (SVs) to obtain large MR outputs for the read sensor applications. The exchange biased SV with Co2 Fe(Al0.5 Si0.5 ) alloy showed a resistance change-area product (Δ RA) of 6 mΩ μm 2 and an MR ratio of 21% at room temperature when the Co2 Fe(Al0.5 Si0.5 ) layer was well-B2-ordered by a high temperature annealing at 500°C. The critical bias current density for the spin torque effect on the reduction of ΔRA was ∼ 3 × 10 7 A/cm2. Based on the high spin polarization directly measured by the point contact Andreev reflection method, Co2 (Cr 0.1 Fe0.9 )Si, Co2 Mn(Ga0.5 Sn 0.5 ), and Co2 Fe(Ge0.5 Ga0.5 ) alloy thin films were investigated for CPP-GMR SVs. Among them, the Co 2Fe(Ge0.5Ga0.5) alloy showed a high CPP-GMR ratio in the pseudo SVs exceeding 40% at RT and 120% at 10 K.

AB - We studied various Heusler alloy compositions for the ferromagnetic layers of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valves (SVs) to obtain large MR outputs for the read sensor applications. The exchange biased SV with Co2 Fe(Al0.5 Si0.5 ) alloy showed a resistance change-area product (Δ RA) of 6 mΩ μm 2 and an MR ratio of 21% at room temperature when the Co2 Fe(Al0.5 Si0.5 ) layer was well-B2-ordered by a high temperature annealing at 500°C. The critical bias current density for the spin torque effect on the reduction of ΔRA was ∼ 3 × 10 7 A/cm2. Based on the high spin polarization directly measured by the point contact Andreev reflection method, Co2 (Cr 0.1 Fe0.9 )Si, Co2 Mn(Ga0.5 Sn 0.5 ), and Co2 Fe(Ge0.5 Ga0.5 ) alloy thin films were investigated for CPP-GMR SVs. Among them, the Co 2Fe(Ge0.5Ga0.5) alloy showed a high CPP-GMR ratio in the pseudo SVs exceeding 40% at RT and 120% at 10 K.

KW - CPP-GMR

KW - Heusler alloy

KW - half-metal

KW - read head

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ER -

Co-based Heusler alloys for CPP-GMR spin-valves with large magnetoresistive outputs

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Keywords

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