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 |
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Pages (from-to) | 14967-14970 |
Number of pages | 4 |
Journal | Journal of Materials Chemistry |
Volume | 21 |
Issue number | 38 |
DOIs | |
Publication status | Published - 2011 Oct 14 |
All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Materials Chemistry