Chemical diffusion: Another factor affecting the magnetoresistance ratio in Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junction

Journal Article · Mon Jul 02 00:00:00 EDT 2012 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4732463· OSTI ID:22089263

Yang, Y.; Wang, W. X.; Yao, Y.; Liu, H. F.; Han, X. F.; Yu, R. C. ^[1]; Naganuma, H.; Sakul, T. S. ^[2]

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1. Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2. Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

This letter investigates the microstructure and mean inner potential (MIP) profile of Ta/CoFeB/MgO/CoFeB/Ta magnetic tunnel junctions (MTJs) by high resolution transmission electron microscopy (HRTEM) and electron holography, respectively. The inconspicuous crystallization of MgO barrier is confirmed by HRTEM in the post-annealed sample at 250 Degree-Sign C. An obvious MIP difference is displayed in the Ta layers between the top and bottom of the MTJ, and elemental content difference of them is confirmed by energy dispersive spectroscopy. These results imply that the chemical diffusion can also give rise to a lower tunnel magnetoresistance ratio besides the inconspicuous crystallization of MgO barrier.

• OSTI ID: 22089263
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 1 Vol. 101; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BORON ALLOYS
CHEMICAL ANALYSIS
COBALT ALLOYS
CRYSTAL STRUCTURE
CRYSTALLIZATION
DIFFUSION
HOLOGRAPHY
IRON ALLOYS
LAYERS
MAGNESIUM OXIDES
MAGNETORESISTANCE
MICROSTRUCTURE
RESOLUTION
SPECTROSCOPY
SUPERCONDUCTING JUNCTIONS
TANTALUM
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
X RADIATION