Direct observation of spin-resolved valence band electronic states from a buried magnetic layer with hard X-ray photoemission
| Autor: | Yuya Sakuraba, Shigenori Ueda |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
502 electron spectroscopy spin-resolved valence band photoemission buried ferromagnetic material Astrophysics::High Energy Astrophysical Phenomena 02 engineering and technology 010402 general chemistry 01 natural sciences Electronic states X-ray photoelectron spectroscopy Physics::Atomic and Molecular Clusters General Materials Science bulk-sensitive electronic state Thin film Spin (physics) Materials of engineering and construction. Mechanics of materials X ray photoemission Condensed matter physics 203 magnetics/spintronics/superconductors hard x-ray photoelectron spectroscopy (haxpes) Direct observation 700 others (development of spin-resolved HAXPES) Optical Magnetic and Electronic Device Materials 021001 nanoscience & nanotechnology 0104 chemical sciences 40 opticalmagnetic electronic device materials Valence band TA401-492 Magnetic layer Condensed Matter::Strongly Correlated Electrons 0210 nano-technology TP248.13-248.65 Research Article Biotechnology |
| Zdroj: | Science and Technology of Advanced Materials, Vol 22, Iss 1, Pp 317-325 (2021) Science and Technology of Advanced Materials article-version (VoR) Version of Record |
| ISSN: | 1878-5514 1468-6996 |
| Popis: | We report spin-resolved hard X-ray photoelectron spectroscopy (spin-HAXPES) for a buried Fe thin film in the valence band region. For the spin-HAXPES experiments, we developed an ultracompact built-in Mott-type spin-filter in a sample carrier, which enabled us to use the merit of two-dimensional (2D) multi-channel detector in a recent photoelectron analyser without modifying an apparatus for HAXPES. The effective Sherman function and the single-channel figure of merit (FOM) of the spin-filter were assessed to be −0.07 and 2.0 × 10−4, respectively. By utilizing the 2D detector of the photoelectron analyser, the effective FOM increased by a factor of ~4 × 104 compared to the case when only 1 channel of the 2D detector was used. We have applied spin-HAXPES to MgO(2 nm)/Fe(50 nm)/MgO(001) structures. The spin-HAXPES experiments revealed the majority and minority spin electronic states and the spin polarisation of the buried Fe thin film. Due to the large photoionization cross-section of the 4s orbital of Fe in HAXPES, the spin-resolved spectra mainly reflected the Fe 3d and 4s states. The observed spin-HAXPES and spin polarisation spectral shapes agreed well with the calculated spin-resolved cross-section weighted densities of states and spin polarisation spectra. In contrast, a small discrepancy in the energy scale was recognised due to the electron correlation effects. These results suggest that the electron correlation effects are important in the electronic structure of bulk Fe, and spin-HAXPES is useful for detecting genuine spin-resolved valence band electronic structures of buried magnetic materials. Graphical abstract |
| Databáze: | OpenAIRE |
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