Probing the electronic states of high-TMR off-stoichiometric Co 2 MnSi thin films by hard x-ray photoelectron spectroscopy
Kozina X, Karel J, Ouardi S, Chadov S, Fecher GH, Felser C, Stryganyuk G, Balke B, Ishikawa T, Uemura T, Yamamoto M, Ikenaga E, Ueda S, Kobayashi K (2014)
Publication Type: Journal article
Publication year: 2014
Journal
Book Volume: 89
Article Number: 125116
Journal Issue: 12
DOI: 10.1103/PhysRevB.89.125116
Abstract
The tunnel magnetoresistance ratio (TMR) of fully epitaxial magnetic tunnel junctions with an off-stoichiometric Co2MnSi Heusler alloy has been shown to exhibit a systematic dependence on Mn content, reaching 1135% at 4.2 K for Co2Mn1.29Si. In this paper, we explain the behavior of the observed TMR ratio using ab initio calculations and hard x-ray photoelectron spectroscopy (HAXPES). For the Mn-deficient samples, we show that the the drop of the TMR is caused by Co antisite atoms, which impose extra states into the minority-spin band gap. On the other hand, Mn-excess composition shows nearly half-metallic behavior. This result can be intuitively understood since both Co2MnSi and Mn2CoSi are theoretically predicted to be half-metallic ferromagnets. © 2014 American Physical Society.
Involved external institutions
Japan Synchrotron Radiation Research Institute (JASRI)
Japan (JP)
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids
Germany (DE)
Johannes Gutenberg-Universität Mainz (JGU)
Germany (DE)
Hokkaido University (Hokudai) / 北海道大学
Japan (JP)
National Institute of Materials Science (NIMS)
Japan (JP)
Japan (JP)
Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids
Germany (DE)
Johannes Gutenberg-Universität Mainz (JGU)
Germany (DE)
Hokkaido University (Hokudai) / 北海道大学
Japan (JP)
National Institute of Materials Science (NIMS)
Japan (JP)
How to cite
APA:
Kozina, X., Karel, J., Ouardi, S., Chadov, S., Fecher, G.H., Felser, C.,... Kobayashi, K. (2014). Probing the electronic states of high-TMR off-stoichiometric Co 2 MnSi thin films by hard x-ray photoelectron spectroscopy. Physical Review B - Condensed Matter and Materials Physics, 89(12). https://doi.org/10.1103/PhysRevB.89.125116
MLA:
Kozina, Xeniya, et al. "Probing the electronic states of high-TMR off-stoichiometric Co 2 MnSi thin films by hard x-ray photoelectron spectroscopy." Physical Review B - Condensed Matter and Materials Physics 89.12 (2014).
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