Effect of diffused b during annealing on the electronic structure of the MgO barrier in CoFeB/MgO/CoFeB magnetic tunnel junctions

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

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We investigate the chemical state and electronic structure of boron in the MgO layer in CoFeB/MgO/CoFeB magnetic tunnel junctions by synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations. In the top CoFeB, we observe three boron 1s peaks corresponding to oxidic, intermediate, and metallic boron. As the annealed films were etched, the B 2O 3 starts to appear together with the Mg 2p peak, indicating that boron atoms diffuse into the MgO barrier. Our calculations show that B impurities in the MgO barrier do not create any midgap states but reduce the MgO barrier height with the increase of boron concentration.

Original languageEnglish
Article number033001
JournalApplied Physics Express
Volume5
Issue number3
DOIs
Publication statusPublished - 2012 Mar 1

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Tunnel junctions
tunnel junctions
Electronic structure
Boron
boron
Annealing
electronic structure
annealing
Synchrotron radiation
synchrotron radiation
X ray photoelectron spectroscopy
photoelectron spectroscopy
Impurities
impurities
Atoms
atoms
x rays

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

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title = "Effect of diffused b during annealing on the electronic structure of the MgO barrier in CoFeB/MgO/CoFeB magnetic tunnel junctions",
abstract = "We investigate the chemical state and electronic structure of boron in the MgO layer in CoFeB/MgO/CoFeB magnetic tunnel junctions by synchrotron radiation X-ray photoelectron spectroscopy and first-principles calculations. In the top CoFeB, we observe three boron 1s peaks corresponding to oxidic, intermediate, and metallic boron. As the annealed films were etched, the B 2O 3 starts to appear together with the Mg 2p peak, indicating that boron atoms diffuse into the MgO barrier. Our calculations show that B impurities in the MgO barrier do not create any midgap states but reduce the MgO barrier height with the increase of boron concentration.",
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Effect of diffused b during annealing on the electronic structure of the MgO barrier in CoFeB/MgO/CoFeB magnetic tunnel junctions. / Han, Yoonsung; Han, Jinhee; Choi, Hyoung Joon; Shin, Hyun Joon; Hong, Jongill.

In: Applied Physics Express, Vol. 5, No. 3, 033001, 01.03.2012.

Research output: Contribution to journalArticle

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AU - Han, Yoonsung

AU - Han, Jinhee

AU - Choi, Hyoung Joon

AU - Shin, Hyun Joon

AU - Hong, Jongill

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