Fig.1 Photoemission spectra at normal emission angle of Cu/FeCo/MgO(100) 57P2-01Electronic State Analysis of Ultra-thin Cu Film on FeCo/MgO(100)Shingo Takezawa1,2, S. Takase1,2, D. Ishikawa1,2, T. Osawa1,2, R. Goto1,2, Y. Sakuraba2, S. Tsuda2, K. Yaji2,3,K. Fuku1,2, M. Imamura4, M. Kotsugi1, and N. Nagamura1,21 Tokyo University of Science, 2 National Institute for Materials Science, 3Tohoku University, 4 Saga UniversityThe structures and electronic states of magnetic multilayers are important research topics in spintronics. FeCo/bcc-Cu/FeCo trilayers have been reported to achieve a good magnetoresistance ratio (42%)[1], but its electronic states remain unknown because of the difficulty to synthesize metastable bcc-Cu. In this study, we prepared Cu/FeCo/MgO by molecular beam epitaxy (MBE) and evaluated its band dispersions by ARPES with synchrotron radiation.The Cu/FeCo thin films were grown on MgO(100) substrates by MBE in UHV chamber connected with the APRES measurement setup. The ARPES measurements were performed at Saga University Beamline (BL13) in SAGA-LS. Low-energy electron diffraction (LEED) was used for in-situ structural evaluation. X-Ray diffraction (XRD) was used for ex-situ structural evaluation. Fig.1 is the energy distribution curve of Cu(2 nm)/FeCo(20 nm)/MgO(100) at normal emission angle as a function of photon energy from hν = 45 eV to 180 eV. The bands between initial state energy 2 and 5 eV exhibit d-like bulk bands. The bands marked as bold lines in Fig.1 is suggested to be derived from bulk band structures specific to bcc-Cu and bcc-FeCo, instead of fcc-Cu, which are predicted from calculations[4-5].[1] K. B. Fathoni et al., APL Mater., 7, 111106 (2019). [2] J. L. Alfke et al., Phys. Chem. Chem. Phys., 24, 24429 (2022). [3] H. Li et al., Phys. Rev. B, 43, 6342, (1991). [4] Z. Tang et al., Phys. Rev. B, 65, 195108 (2002). [5] V. T, Tran et al., Computational Materials Science, 172, 109344, (2022).P2-02Electronic Properties of Chemical Vapor Deposition-grown Graphene on Ni (111) Investigated by Spin- and Angle-resolved Photoemission Spectroscopy Thang Dinh Phan1, S. Tsuda1, R. Goto1,2, N. Nagamura1,2, F. Komori1, Y. Tanimoto3, H. Sato4, Y. Fukushima5,K. Kawaguchi5, R. Mori5, T. Kondo5, Y. Yamaji6, and K. Yaji1,7 1 Center for Basic Research on Materials, NIMS, 2 Faculty of Advanced Engineering, Tokyo Uni. of Science,3 Graduate School of Advanced Science and Engineering, Hiroshima Uni., 4 HiSOR, 5 Institute for Solid State Physics, The Uni. of Tokyo, 6 Research Center for Materials Nanoarchitectonics, NIMS, 7 UDAC, Tohoku Uni. Graphene-based spintronics utilizes the spin degree freedom of graphene’s electrons at the Dirac points near the Fermi level for novel information storage and logic devices. Shifted Dirac-band in previous studies [1] can be improved by using the chemical vapor deposition (CVD)-grown graphene on the Ni (111) substrate. The electronic property of a CVD-grown graphene/Ni (111) has been studied with (spin-) and angle-resolved photoemission spectroscopy ((S)ARPES) measurements [2,3]. We find that the Dirac point of a single dispersive linear π-band nearly the Fermi level. The spin-polarized π-band around the K-point has been confirmed by SARPES, providing a significant advantage for spin transport. In addition, we find other bands with a two-dimensional nature near the Fermi level. [1] A. Varykhalov et al., Phys. Rev. X, 2, 041017 (2012). [2] K. Yaji et al., Sci. Technol. Adv. Mater. Meth., 4, 2328206 (2024). [3] K. Yaji et al., e-J. Surf. Sci. Nanotechnol., 22, 46 (2024). Poster Award NomineePoster Award Nominee
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