In-situ characterization of rapid crystallization of amorphous CoFeB electrodes in CoFeB/MgO/CoFeB junctions during thermal annealing

W. G. Wang, J. Jordan-Sweet, G. X. Miao, C. Ni, A. K. Rumaiz, L. R. Shah, X. Fan, P. Parsons, R. Stearrett, E. R. Nowak, J. S. Moodera, J. Q. Xiao

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30 Scopus citations

Abstract

We report the crystallization study of CoFeB/MgO/CoFeB magnetic tunnel junctions using in-situ, time-resolved synchrotron-based x-ray diffraction and transmission electron microscopy. It was found that the crystallization of amorphous CoFeB electrodes occurs on a time scale of seconds during the postgrowth high temperature annealing. The crystallization can be well fit by the Johnson-Mehl-Avrami model and the effective activation energy of the process was determined to be 150 kJ/mol. The solid-state epitaxy mode of CoFeB was found to involve separate crystallization at different locations followed by subsequent merging of small grains, instead of layer-by-layer growth of CoFeB film along the MgO template.

Original languageEnglish (US)
Article number242501
JournalApplied Physics Letters
Volume95
Issue number24
DOIs
StatePublished - Dec 14 2009
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Wang, W. G., Jordan-Sweet, J., Miao, G. X., Ni, C., Rumaiz, A. K., Shah, L. R., Fan, X., Parsons, P., Stearrett, R., Nowak, E. R., Moodera, J. S., & Xiao, J. Q. (2009). In-situ characterization of rapid crystallization of amorphous CoFeB electrodes in CoFeB/MgO/CoFeB junctions during thermal annealing. Applied Physics Letters, 95(24), [242501]. https://doi.org/10.1063/1.3273397