Magnetotransport in MgO-based magnetic tunnel junctions grown by molecular beam epitaxy (invited)

Journal Article · Wed May 07 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4869824· OSTI ID:22273644

Bonell, F.; Hauet, T.; Montaigne, F. ^[1]; Calmels, L.; Snoeck, E. ^[2]; Lefevre, P.; Bertran, F. ^[3]

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1. Institut Jean Lamour, Nancy University/CNRS, Bd des Aiguillettes, BP239, 54506 Vandoeuvre-lès-Nancy (France)
2. CEMES, CNRS and Toulouse University, 29 rue Jeanne Marvig, 31055 Toulouse (France)
3. Synchrotron SOLEIL-CNRS, L'Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette cedex (France)

The strong impact of molecular beam epitaxy growth and Synchrotron Radiation characterization tools in the understanding of fundamental issues in nanomagnetism and spintronics is illustrated through the example of fully epitaxial MgO-based Magnetic Tunnel Junctions (MTJs). If ab initio calculations predict very high tunnel magnetoresistance (TMR) in such devices, some discrepancy between theory and experiments still exists. The influence of imperfections in real systems has thus to be considered like surface contaminations, structural defects, unexpected electronic states, etc. The influence of possible oxygen contamination at the Fe/MgO(001) interface is thus studied, and is shown to be not so detrimental to TMR as predicted by ab initio calculations. On the contrary, the decrease of dislocations density in the MgO barrier of MTJs using Fe{sub 1−x}V{sub x} electrodes is shown to significantly increase TMR. Finally, unexpected transport properties in Fe{sub 1−X}Co{sub x}/MgO/Fe{sub 1−X}Co{sub x} (001) are presented. With the help of spin and symmetry resolved photoemission and ab initio calculation, the TMR decrease for Co content higher than 25% is shown to come from the existence of an interface state and the shift of the empty Δ1 minority spin state towards the Fermi level.

• OSTI ID: 22273644
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 17; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COBALT
DISLOCATIONS
FERMI LEVEL
HETEROJUNCTIONS
INTERFACES
INTERMETALLIC COMPOUNDS
IRON
MAGNESIUM OXIDES
MAGNETORESISTANCE
MOLECULAR BEAM EPITAXY
PHOTOEMISSION
SPIN
SYNCHROTRON RADIATION
TUNNEL EFFECT