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 journalArticlepeer-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 languageEnglish
Pages (from-to)14967-14970
Number of pages4
JournalJournal of Materials Chemistry
Volume21
Issue number38
DOIs
Publication statusPublished - 2011 Oct 14

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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