Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature

Jun Hayakawa; Shoji Ikeda; Fumihiro Matsukura; Hiromasa Takahashi; Hideo Ohno

doi:10.1143/JJAP.44.L587

Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature

Jun Hayakawa, Shoji Ikeda, Fumihiro Matsukura, Hiromasa Takahashi, Hideo Ohno

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

238 Citations (Scopus)

Abstract

We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO₂/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.

Original language	English
Pages (from-to)	L587-L589
Journal	Japanese Journal of Applied Physics
Volume	44
Issue number	16-19
DOIs	https://doi.org/10.1143/JJAP.44.L587
Publication status	Published - 2005

Keywords

CoFeB
Crystallization
Magnetic tunnel junction
MgO barrier
Tunnel magnetoresistance effect

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10.1143/JJAP.44.L587

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title = "Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature",

abstract = "We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.",

keywords = "CoFeB, Crystallization, Magnetic tunnel junction, MgO barrier, Tunnel magnetoresistance effect",

author = "Jun Hayakawa and Shoji Ikeda and Fumihiro Matsukura and Hiromasa Takahashi and Hideo Ohno",

year = "2005",

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language = "English",

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pages = "L587--L589",

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publisher = "Japan Society of Applied Physics",

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TY - JOUR

T1 - Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature

AU - Hayakawa, Jun

AU - Ikeda, Shoji

AU - Matsukura, Fumihiro

AU - Takahashi, Hiromasa

AU - Ohno, Hideo

PY - 2005

Y1 - 2005

N2 - We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.

AB - We investigated the dependence of giant tunnel magnetoresistance (TMR) on the thickness of an MgO barrier and on the annealing temperature of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions deposited on SiO2/Si wafers. The resistance-area product exponentially increases with MgO thickness, indicating that the quality of MgO barriers is high in the investigated thickness range of 1.15-2.4 nm. High-resolution transmission electron microscope images show that annealing at 375°C results in the formation of crystalline CoFeB/MgO/CoFeB structures, even though CoFeB electrodes are amorphous in the as-sputtered state. The TMR ratio increases with annealing temperature and is as high as 260% at room temperature and 403% at 5 K.

KW - CoFeB

KW - Crystallization

KW - Magnetic tunnel junction

KW - MgO barrier

KW - Tunnel magnetoresistance effect

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DO - 10.1143/JJAP.44.L587

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SN - 0021-4922

VL - 44

SP - L587-L589

JO - Japanese Journal of Applied Physics

JF - Japanese Journal of Applied Physics

IS - 16-19

ER -

Dependence of giant tunnel magnetoresistance of sputtered CoFeB/MgO/CoFeB magnetic tunnel junctions on MgO barrier thickness and annealing temperature

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Keywords

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