Effect of interfacial structures on spin dependent tunneling in epitaxial L1{sub 0}-FePt/MgO/FePt perpendicular magnetic tunnel junctions

Journal Article · Sat Feb 28 04:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4913265· OSTI ID:22413156

Yang, G.; Li, D. L.; Ma, Q. L.; Liang, S. H.; Wei, H. X.; Han, X. F. ^[1]; Hesjedal, T.; Ward, R. C. C. ^[2]; Kohn, A.; Elkayam, A.; Tal, N. ^[3]; Zhang, X. -G. ^[4]

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1. State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
2. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)
3. Department of Materials Engineering and the Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)
4. Department of Physics and Quantum Theory Project, University of Florida, Gainesville, Florida 32611 (United States)

Epitaxial FePt(001)/MgO/FePt magnetic tunnel junctions with L1{sub 0}-FePt electrodes showing perpendicular magnetic anisotropy were fabricated by molecular beam epitaxial growth. Tunnel magnetoresistance ratios of 21% and 53% were obtained at 300 K and 10 K, respectively. Our previous work, based on transmission electron microscopy, confirmed a semi-coherent interfacial structure with atomic steps (Kohn et al., APL 102, 062403 (2013)). Here, we show by x-ray photoemission spectroscopy and first-principles calculation that the bottom FePt/MgO interface is either Pt-terminated for regular growth or when an Fe layer is inserted at the interface, it is chemically bonded to O. Both these structures have a dominant role in spin dependent tunneling across the MgO barrier resulting in a decrease of the tunneling magnetoresistance ratio compared with previous predictions.

• OSTI ID: 22413156
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
COMPARATIVE EVALUATIONS
DIFFUSION BARRIERS
ELECTRODES
INTERFACES
INTERMETALLIC COMPOUNDS
IRON
MAGNESIUM OXIDES
MAGNETORESISTANCE
MOLECULAR BEAM EPITAXY
PHOTOELECTRON SPECTROSCOPY
PLATINUM
SPIN
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT