Microscopic and electronic roles of B in CoFeB-based magnetic tunnel junctions

Yoonsung Han; Jinhee Han; Hyoung Joon Choi; Hyun Joon Shin; Jongill Hong

doi:10.1039/c1jm12096d

Microscopic and electronic roles of B in CoFeB-based magnetic tunnel junctions

Yoonsung Han, Jinhee Han, Hyoung Joon Choi, Hyun Joon Shin, Jongill Hong

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

11 Citations (Scopus)

Abstract

The giant tunneling magnetoresistance (TMR) in lattice-matched crystalline magnetic tunnel junctions (MTJs) strongly depends on the majority-spin Δ₁ bands of ferromagnetic electrodes. Our synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations show that B atoms suppress the formation of CoFe-O during CoFeB deposition in CoFeB/MgO/CoFeB MTJs, thereby lessening an effect that significantly degrades the majority-spin Δ₁ bands, and that CoFe-B has properties superior to CoFe-O in electron conduction in the majority-spin Δ₁ bands. During annealing, some of the B in CoFeB diffuses out, enhancing the valence bands of metallic CoFe, which improves the TMR value even further. Our present work elucidates the microscopic and electronic roles of B in MgO MTJs with CoFeB electrodes.

Original language	English
Pages (from-to)	14967-14970
Number of pages	4
Journal	Journal of Materials Chemistry
Volume	21
Issue number	38
DOIs	https://doi.org/10.1039/c1jm12096d
Publication status	Published - 2011 Oct 14

All Science Journal Classification (ASJC) codes

Chemistry(all)
Materials Chemistry

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title = "Microscopic and electronic roles of B in CoFeB-based magnetic tunnel junctions",

abstract = "The giant tunneling magnetoresistance (TMR) in lattice-matched crystalline magnetic tunnel junctions (MTJs) strongly depends on the majority-spin Δ1 bands of ferromagnetic electrodes. Our synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations show that B atoms suppress the formation of CoFe-O during CoFeB deposition in CoFeB/MgO/CoFeB MTJs, thereby lessening an effect that significantly degrades the majority-spin Δ1 bands, and that CoFe-B has properties superior to CoFe-O in electron conduction in the majority-spin Δ1 bands. During annealing, some of the B in CoFeB diffuses out, enhancing the valence bands of metallic CoFe, which improves the TMR value even further. Our present work elucidates the microscopic and electronic roles of B in MgO MTJs with CoFeB electrodes.",

author = "Yoonsung Han and Jinhee Han and Choi, {Hyoung Joon} and Shin, {Hyun Joon} and Jongill Hong",

year = "2011",

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doi = "10.1039/c1jm12096d",

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publisher = "Royal Society of Chemistry",

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T1 - Microscopic and electronic roles of B in CoFeB-based magnetic tunnel junctions

AU - Han, Yoonsung

AU - Han, Jinhee

AU - Choi, Hyoung Joon

AU - Shin, Hyun Joon

AU - Hong, Jongill

PY - 2011/10/14

Y1 - 2011/10/14

N2 - The giant tunneling magnetoresistance (TMR) in lattice-matched crystalline magnetic tunnel junctions (MTJs) strongly depends on the majority-spin Δ1 bands of ferromagnetic electrodes. Our synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations show that B atoms suppress the formation of CoFe-O during CoFeB deposition in CoFeB/MgO/CoFeB MTJs, thereby lessening an effect that significantly degrades the majority-spin Δ1 bands, and that CoFe-B has properties superior to CoFe-O in electron conduction in the majority-spin Δ1 bands. During annealing, some of the B in CoFeB diffuses out, enhancing the valence bands of metallic CoFe, which improves the TMR value even further. Our present work elucidates the microscopic and electronic roles of B in MgO MTJs with CoFeB electrodes.

AB - The giant tunneling magnetoresistance (TMR) in lattice-matched crystalline magnetic tunnel junctions (MTJs) strongly depends on the majority-spin Δ1 bands of ferromagnetic electrodes. Our synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations show that B atoms suppress the formation of CoFe-O during CoFeB deposition in CoFeB/MgO/CoFeB MTJs, thereby lessening an effect that significantly degrades the majority-spin Δ1 bands, and that CoFe-B has properties superior to CoFe-O in electron conduction in the majority-spin Δ1 bands. During annealing, some of the B in CoFeB diffuses out, enhancing the valence bands of metallic CoFe, which improves the TMR value even further. Our present work elucidates the microscopic and electronic roles of B in MgO MTJs with CoFeB electrodes.

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Microscopic and electronic roles of B in CoFeB-based magnetic tunnel junctions

Abstract

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