Structural characterization of interfaces in epitaxial Fe/MgO/Fe magnetic tunnel junctions by transmission electron microscopy

Journal Article · Thu Jul 01 00:00:00 EDT 2010 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.82.024428· OSTI ID:21386914

Wang, C; Chang, L Y; Choi, S -Y; Kirkland, A I ^[1]; Kohn, A ^[2]; Wang, S G ^[3]; Petford-Long, A K ^[4]; Ward, R C. C. ^[3]

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1. Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom)
2. Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)
3. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)
4. Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439 (United States)

We present a detailed structural characterization of the interfaces in Fe/MgO/Fe layers grown by molecular-beam epitaxy using aberration-corrected transmission electron microscopy (TEM), scanning TEM, and electron energy-loss spectroscopy. When fabricated into magnetic tunnel junctions, these epitaxial devices exhibit large tunnel magnetoresistance ratios (e.g., 318% at 10 K), though still considerably lower than the values predicted theoretically. The reason for this discrepancy is being debated and has been attributed to the structure of, and defects at the interface, namely, the relative position of the atoms, interface oxidation, strain, and structural asymmetry of the interfaces. In this structural study, we observed that Fe is bound to O at the interfaces. The interfaces are semicoherent and mostly sharp with a minor degree of oxidation. A comparison of the two interfaces shows that the top MgO/Fe interface is rougher.

• OSTI ID: 21386914
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 82, Issue 2; Other Information: DOI: 10.1103/PhysRevB.82.024428; (c) 2010 The American Physical Society; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ASYMMETRY
ATOMS
COMPARATIVE EVALUATIONS
CRYSTAL DEFECTS
ELECTRONS
ENERGY-LOSS SPECTROSCOPY
INTERFACES
IRON
LAYERS
MAGNESIUM OXIDES
MAGNETORESISTANCE
MOLECULAR BEAM EPITAXY
OXIDATION
STRAINS
SUPERCONDUCTING JUNCTIONS
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTARY PARTICLES
ELEMENTS
EPITAXY
EVALUATION
FERMIONS
LEPTONS
MAGNESIUM COMPOUNDS
METALS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SPECTROSCOPY
TRANSITION ELEMENTS