Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance

Sung Hoon Kim; Byong Sun Chun; Young Keun Kim; Seong Rae Lee

doi:10.1007/BF03027231

Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance

Sung Hoon Kim, Byong Sun Chun, Young Keun Kim, Seong Rae Lee

Department of Materials Science and Engineering

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

1 Citation (Scopus)

Abstract

We have investigated the temperature dependence of tunneling magnetoresistance (TMR) on plasma oxidation time and annealing temperature. Magnetic tunnel junctions comprising Si/SiO₂/Ta/CoFe/IrMn/CoFe5/Al1.6 (oxidized)/CoFe5/Ta (in nm) were sputter-deposited. Thin tunnel barriers were formed by oxidizing Al layers under oxygen plasma for 30-70 sec. When needed, post-deposition annealing was carried out at 450-500 K for 20 min under 500 Oe of external magnetic field. The temperature dependence of such samples was measured between 10 K and 300 K using a cryogenic MR tester. The spin polarization behavior was represented as P(T)=P₀(1-αT ^1.5), where P₀ and α are spin polarization value and spin wave parameter, respectively. It appeared that there was an optimum oxidation condition that resulted in the highest P₀ (40.3 %) and the lowest a((10±4.742)×10^-6 K^-1.5). At this condition, the tunnel barrier is thought to possess the least amount of residual Al or magnetic dead layers at the barrier/ferromagnet interface. The sample that underwent 450 K annealing resulted in a slight enhancement in spin polarization.

Original language	English
Pages (from-to)	57-59
Number of pages	3
Journal	Metals and Materials International
Volume	9
Issue number	1
DOIs	https://doi.org/10.1007/BF03027231
Publication status	Published - 2003 Feb

Keywords

Magnetic tunnel junction
Oxidation and annealing
Temperature dependence
Tunneling magnetoresistance

ASJC Scopus subject areas

Condensed Matter Physics
Mechanics of Materials
Metals and Alloys
Materials Chemistry

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10.1007/BF03027231

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title = "Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance",

abstract = "We have investigated the temperature dependence of tunneling magnetoresistance (TMR) on plasma oxidation time and annealing temperature. Magnetic tunnel junctions comprising Si/SiO2/Ta/CoFe/IrMn/CoFe5/Al1.6 (oxidized)/CoFe5/Ta (in nm) were sputter-deposited. Thin tunnel barriers were formed by oxidizing Al layers under oxygen plasma for 30-70 sec. When needed, post-deposition annealing was carried out at 450-500 K for 20 min under 500 Oe of external magnetic field. The temperature dependence of such samples was measured between 10 K and 300 K using a cryogenic MR tester. The spin polarization behavior was represented as P(T)=P0(1-αT 1.5), where P0 and α are spin polarization value and spin wave parameter, respectively. It appeared that there was an optimum oxidation condition that resulted in the highest P0 (40.3 %) and the lowest a((10±4.742)×10-6 K-1.5). At this condition, the tunnel barrier is thought to possess the least amount of residual Al or magnetic dead layers at the barrier/ferromagnet interface. The sample that underwent 450 K annealing resulted in a slight enhancement in spin polarization.",

keywords = "Magnetic tunnel junction, Oxidation and annealing, Temperature dependence, Tunneling magnetoresistance",

author = "Kim, {Sung Hoon} and Chun, {Byong Sun} and Kim, {Young Keun} and Lee, {Seong Rae}",

note = "Funding Information: This work was supported by the Korea Ministry of Science and Technology under the National Research Laboratory program, the National Program for Tera-level Nanodevices, and by grant No. R01-2000-000-00234-0 from the Basic Research Program of the Korea Science & Engineering Foundation.",

year = "2003",

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doi = "10.1007/BF03027231",

language = "English",

volume = "9",

pages = "57--59",

journal = "Metals and Materials International",

issn = "1598-9623",

publisher = "Korean Institute of Metals and Materials",

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TY - JOUR

T1 - Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance

AU - Kim, Sung Hoon

AU - Chun, Byong Sun

AU - Kim, Young Keun

AU - Lee, Seong Rae

N1 - Funding Information: This work was supported by the Korea Ministry of Science and Technology under the National Research Laboratory program, the National Program for Tera-level Nanodevices, and by grant No. R01-2000-000-00234-0 from the Basic Research Program of the Korea Science & Engineering Foundation.

PY - 2003/2

Y1 - 2003/2

N2 - We have investigated the temperature dependence of tunneling magnetoresistance (TMR) on plasma oxidation time and annealing temperature. Magnetic tunnel junctions comprising Si/SiO2/Ta/CoFe/IrMn/CoFe5/Al1.6 (oxidized)/CoFe5/Ta (in nm) were sputter-deposited. Thin tunnel barriers were formed by oxidizing Al layers under oxygen plasma for 30-70 sec. When needed, post-deposition annealing was carried out at 450-500 K for 20 min under 500 Oe of external magnetic field. The temperature dependence of such samples was measured between 10 K and 300 K using a cryogenic MR tester. The spin polarization behavior was represented as P(T)=P0(1-αT 1.5), where P0 and α are spin polarization value and spin wave parameter, respectively. It appeared that there was an optimum oxidation condition that resulted in the highest P0 (40.3 %) and the lowest a((10±4.742)×10-6 K-1.5). At this condition, the tunnel barrier is thought to possess the least amount of residual Al or magnetic dead layers at the barrier/ferromagnet interface. The sample that underwent 450 K annealing resulted in a slight enhancement in spin polarization.

AB - We have investigated the temperature dependence of tunneling magnetoresistance (TMR) on plasma oxidation time and annealing temperature. Magnetic tunnel junctions comprising Si/SiO2/Ta/CoFe/IrMn/CoFe5/Al1.6 (oxidized)/CoFe5/Ta (in nm) were sputter-deposited. Thin tunnel barriers were formed by oxidizing Al layers under oxygen plasma for 30-70 sec. When needed, post-deposition annealing was carried out at 450-500 K for 20 min under 500 Oe of external magnetic field. The temperature dependence of such samples was measured between 10 K and 300 K using a cryogenic MR tester. The spin polarization behavior was represented as P(T)=P0(1-αT 1.5), where P0 and α are spin polarization value and spin wave parameter, respectively. It appeared that there was an optimum oxidation condition that resulted in the highest P0 (40.3 %) and the lowest a((10±4.742)×10-6 K-1.5). At this condition, the tunnel barrier is thought to possess the least amount of residual Al or magnetic dead layers at the barrier/ferromagnet interface. The sample that underwent 450 K annealing resulted in a slight enhancement in spin polarization.

KW - Magnetic tunnel junction

KW - Oxidation and annealing

KW - Temperature dependence

KW - Tunneling magnetoresistance

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U2 - 10.1007/BF03027231

DO - 10.1007/BF03027231

M3 - Article

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SN - 1598-9623

VL - 9

SP - 57

EP - 59

JO - Metals and Materials International

JF - Metals and Materials International

IS - 1

ER -

Effect of Plasma Oxidation Time and Annealing Condition on the Temperature Dependence of Tunneling Magnetoresistance

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