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^*

^*Corresponding author for this work

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

Bibliographical 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.

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

Cite this

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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",

month = feb,

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",

number = "1",

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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

UR - https://www.scopus.com/pages/publications/1842525047

U2 - 10.1007/BF03027231

DO - 10.1007/BF03027231

M3 - Article

AN - SCOPUS:1842525047

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

Abstract

Bibliographical note

Keywords

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