The 82nd JSAP Autumn Meeting 2021

Presentation information

Oral presentation

10 Spintronics and Magnetics » 10.1 Emerging materials in spintronics and magnetics (including fabrication and characterization methodologies)

[13p-S302-1~15] 10.1 Emerging materials in spintronics and magnetics (including fabrication and characterization methodologies)

Mon. Sep 13, 2021 1:30 PM - 5:45 PM S302 (Oral)

Takeshi Seki(Tohoku Univ.), Taro Nagahama(Hokkaido Univ.), Shinya Kasai(NIMS)

1:30 PM - 1:45 PM

[13p-S302-1] Two-dimensional Electronic State in a Ferromagnetic L10 MnGa Thin Film with Perpendicular Magnetization

MASAKI KOBAYASHI1,2, N. H. D. Khang3, Takahito Takeda1, Kohsei Araki1, Ryo Okano1, Masahiro Suzuki4, Kenta Kuroda5, Koichiro Yaji6, Katsuaki Sugawara7,8,9,10, Seigo Souma8,9, Kosuke Nakayama7,10, Miho Kitamura11, Koji Horiba11, Atsushi Fujimori4,12, Takafumi Sato7,8,9,5, Shik Shin5, Masaaki Tanaka1,2, Pham Nam Hai2,3 (1.Grad. Sch. Eng., Univ. of Tokyo, 2.CSRN, Univ. of Tokyo, 3.Tokyo Tech., 4.Dep. Phys., Univ. of Tokyo, 5.ISSP, Univ. of Tokyo, 6.NIMS, 7.Dep. Phys., Tohoku Univ., 8.WPI-AIMR, Tohoku Univ., 9.CSRN, Tohoku Univ., 10.JST-PREST, 11.KEK-IMSS, 12.Dep. Appl. Phys., Waseda Univ.)

Keywords:Perpendicular magnetization, Electronic state, Angle-resolved photoemission spectroscopy

Ferromagnetic thin films with perpendicular magnetization are key materials for high-density magnetic recording and other spintronics applications. Mn1-xGax thin films with the L10 (or CuAu type) crystal structure (referred to as MnGa), which show strong perpendicular magnetic anisotropy (PMA), were successfully grown by molecular beam epitaxy (MBE) in the early 1990s. Recently, spintronic device structures using MnGa layers have been studied, such as magnetic tunnel junctions and spin-orbit torque devices. To understand the properties of MaGa and the heterostructures using MnGa, it is important to characterize the electronic properties of MnGa. In this study, we have performed angle-resolved photoemission spectroscopy (ARPES) with vacuum ultra-violet light on a L10 MnGa thin film with PMA to elucidate the electronic states.
The in-plane Fermi surface mapping demonstrates a diamond-like Fermi surface (FS) in the kx-ky (the [100] and [010] directions) plane. The large area of FS is consistent with the metallic nature of MnGa. This FS was likely independent of photon energy, indicating that the FS originates from two-dimensional (2D) bands. In contrast, the bulk band dispersion below the Fermi level changes with kz. Since MnGa has the three-dimensional L10 crystal structure, the observed 2D electronic state is expected to come from surface states. To the authors’ knowledge, this is the first observation of the band dispersion in a MnGa film with the clean surface using ARPES.

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