Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 52: Poster II
MA 52.50: Poster
Donnerstag, 15. März 2018, 15:00–18:00, Poster C
Electronic structure of high-TMR off-stoichiometric Co2(Mn,Fe)Si Heusler thin films explored by hard X-ray photoelectron spectroscopy — •Siham Ouardi1, Kidist Moges2, Bing Hu2, Gerhard H. Fecher3, Masafumi Yamamoto2, Tetsuya Uemura2, Shigenori Ueda4, and Claudia Felser3 — 1WPI Ad-vanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan — 2Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan — 3Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 4National Institute for Materials Science, SPring-8, Hyogo, Japan
The quaternary Heuslers alloy Co2(Mn,Fe)Si are among the most promising half-metallic ferromagnets and suitable as a spin source for spintronic devices. A giant tunneling magnetoresistance (TMR) ratio up to 2610% at 4.2 K (429% at 290 K) was realized on Co2(Mn,Fe)Si/MgO/Co2(Mn,Fe)Si magnetic tunnel junctions (MTJs) with Mn-rich, lightly Fe-doped Co2(Mn,Fe)Si electrodes [1]. This work reports on the investigation of the electronic states of off-stoichiometric Co2(Mn,Fe)Si Heusler thin films by hard X-ray photoelectron spectroscopy in combination with band structure calculations. Co, Fe, and Mn states are probed by magnetic dichroism in angle-resolved photoelectron spectroscopy at the 2p core levels. The effect of the Fe doping, as well as the antisite disorder on the valence states at the Fermi edge will be discussed.
[1] K. Moges, et al. Phys. Rev. B 93, 134403 (2016).