Temperature-dependent Mn diffusion modes in amorphous CoFeB and crystalline CoFe-based magnetic tunnel junctions
- Institute of Physics, Chinese Academy of Science
- ORNL
- Hubei University
- Beijing University of Technology
We show that Mn atoms diffuse with two different mechanisms at high and low temperatures in CoFeB and CoFe-based magnetic tunnel junctions. By combining high resolution and scanning transmission electron microscopy, we reveal that below 300\textordmasculine C the amorphous CoFeB and the textured CoFe are equally effective in blocking the diffusion of Mn, contradicting the conventional wisdom that the diffusion occurs primarily along grain boundaries. Below 300\textordmasculine C Mn diffusion in crystalline CoFe occurs through the bulk and is assisted by oxygen atoms which only diffuse parallel to the bcc close-packed (110) plane. Above 300\textordmasculine C Mn diffuses through vacancies along the grain boundaries of CoFe and in the bulk of amorphous CoFeB. A universal diffusion temperature is proposed based on an isokinetic relation.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 931653
- Journal Information:
- Physical Review B, Vol. 75
- Country of Publication:
- United States
- Language:
- English
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