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

Abstract

In this study, epitaxial FePt(001)/MgO/FePt magnetic tunnel junctions with L1 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. Finally, 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.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1]; ORCiD logo [2];  [2];  [3];  [3];  [3];  [4]
  1. Chinese Academy of Sciences (CAS), Beijing (China). State Key Lab. of Magnetism. Beijing National Lab. for Condensed Matter Physics. Inst. of Physics
  2. Univ. of Oxford (United Kingdom). Clarendon Lab. Dept. of Physics
  3. Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Materials Engineering. Ilse Katz Inst. for Nanoscale Science and Technology
  4. Univ. of Florida, Gainesville, FL (United States). Dept. of Physics. Quantum Theory Project; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Computer Science and Mathematics Division
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
Chinese Academy of Sciences (CAS), Beijing (China); Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel)
OSTI Identifier:
1265531
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 8; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; interface structure; magnetic tunnel junctions; tunneling; epitaxy; electrodes

Citation Formats

Yang, G., Li, D. L., Wang, S. G., Ma, Q. L., Liang, S. H., Wei, H. X., Han, X. F., Hesjedal, T., Ward, R. C. C., Kohn, A., Elkayam, A., Tal, N., and Zhang, X. -G. Effect of interfacial structures on spin dependent tunneling in epitaxial L10-FePt/MgO/FePt perpendicular magnetic tunnel junctions. United States: N. p., 2015. Web. doi:10.1063/1.4913265.
Yang, G., Li, D. L., Wang, S. G., Ma, Q. L., Liang, S. H., Wei, H. X., Han, X. F., Hesjedal, T., Ward, R. C. C., Kohn, A., Elkayam, A., Tal, N., & Zhang, X. -G. Effect of interfacial structures on spin dependent tunneling in epitaxial L10-FePt/MgO/FePt perpendicular magnetic tunnel junctions. United States. doi:10.1063/1.4913265.
Yang, G., Li, D. L., Wang, S. G., Ma, Q. L., Liang, S. H., Wei, H. X., Han, X. F., Hesjedal, T., Ward, R. C. C., Kohn, A., Elkayam, A., Tal, N., and Zhang, X. -G. Tue . "Effect of interfacial structures on spin dependent tunneling in epitaxial L10-FePt/MgO/FePt perpendicular magnetic tunnel junctions". United States. doi:10.1063/1.4913265. https://www.osti.gov/servlets/purl/1265531.
@article{osti_1265531,
title = {Effect of interfacial structures on spin dependent tunneling in epitaxial L10-FePt/MgO/FePt perpendicular magnetic tunnel junctions},
author = {Yang, G. and Li, D. L. and Wang, S. G. and Ma, Q. L. and Liang, S. H. and Wei, H. X. and Han, X. F. and Hesjedal, T. and Ward, R. C. C. and Kohn, A. and Elkayam, A. and Tal, N. and Zhang, X. -G.},
abstractNote = {In this study, epitaxial FePt(001)/MgO/FePt magnetic tunnel junctions with L10-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. Finally, 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.},
doi = {10.1063/1.4913265},
journal = {Journal of Applied Physics},
number = 8,
volume = 117,
place = {United States},
year = {2015},
month = {2}
}

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Works referenced in this record:

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Soft self-consistent pseudopotentials in a generalized eigenvalue formalism
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