2016S2-005
新規スピントロニクス材料の薄膜・界面が示す特異な物性の多自由度軟X線分光

Last modified 2023-07-18 by s-proposalpfiqst.kek.jp

●基本情報
　●実験責任者：藤森　淳（東大理）
　●課題有効期間：2016/10〜2019/9
　●実験ステーション：16A,7A,12C,4C
　●関連課題：2013S2-004（外的要因による磁性薄膜の特性制御を目指した軟X線XMCDを中心とする相補的研究）
　　　　　　　2010S2-001（軟X線偏光スイッチングを用いたスピントロニクス材料の探求）

●課題の概要
　本課題は、スピントロニクス材料としての応用が期待される新規磁性薄膜・多層膜について、軟X線XMCDを中心とした複数の相補的な実験手法を組み合わせることによって、磁気モーメントの異方性や空間分布といったミクロな磁気状態を多面的に明らかにすること、さらにそれを手掛かりに磁気特性の発現メカニズムの解明や磁気特性の制御につなげていくことを目的とする。試料作製グループと緊密に連携し、単に分光測定を行うのみならず、そこから得られた情報を基に狙った磁気特性を示す新たな試料の作製へとつなげていくことを重視して研究を行う。特に、外的要因を変化させた場合のミクロ磁気状態の変化を詳細に調べることにより、磁性薄膜・多層膜の物性の制御方法に関して重要な手掛かりが得ることを狙っている。
　本研究は以下の特色を持つ。
（１）深さ分解XMCD・ベクトル磁場XMCDなど、申請者らが開発した独自性の高い実験手法を駆使し、従来のXMCD実験やその他の分光手法では得られなかった磁性に関する情報を明らかにする。
（２）S課題の長いビームタイムを活用し、1つの試料系に対しなるべく多くのプローブを相補的に用いて、磁性薄膜の磁気状態、電子状態、結晶構造を総合的に明らかにする。その情報を用いて、磁気特性の発現機構をも明らかにする。
（３）単に測定・解析を行うだけでなく、その情報をもとに新規物質を設計してフィードバックする。特に申請者の一部は物質作製に精通しており、かつ実験グループがPF内や筑波大学にあるため、S課題の柔軟性と相まって高速なフィードバックが期待できる。
（４）In situ実験を行う金属薄膜・多層膜に関しては、測定した結果をもとに翌日の試料を作製することができるため、さらに高速のフィードバックが可能になる。

●成果発表
　●論文

• "Origin of magnetically dead layers in spinel ferrites MFe₂O₄ grown on Al₂O₃: Effects of postdeposition annealing studied by XMCD"
  Yosuke Nonaka, Yuki K. Wakabayashi, Goro Shibata, Shoya Sakamoto, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Arata Tanaka, Masaaki Tanaka, and Atsushi Fujimori
  Phys. Rev. Materials, 7 (2023) 044413.
• "Cr doping-induced ferromagnetism in the spin-glass Cd_1−xMn_xTe studied by x-ray magnetic circular dichroism"
  V.K.Verma, S.Sakamoto, K.Ishikawa, V.R.Singh, K.Ishigami, G.Shibata, T.Kadono, T.Koide, S.Kuroda, A.Fujimoria
  Physica B: Condensed Matter, 642 (2022) 414129.
• "Magnetic anisotropy of the van der Waals ferromagnet Cr₂Ge₂Te₆ studied by angular-dependent x-ray magnetic circular dichroism"
  M. Suzuki, B. Gao, G. Shibata, S. Sakamoto, Y. Nonaka, K. Ikeda, Z. Chi, Y.-X. Wan, T. Takeda, Y. Takeda, T. Koide, A. Tanaka, M. Kobayashi, S.-W. Cheong, and A. Fujimori
  Phys. Rev. Research, 4 (2022) 013139.
• "Strain Engineering of Magnetic Anisotropy in Epitaxial Films of Cobalt Ferrite"
  Hiroshige Onoda, Hiroaki Sukegawa, Jun-Ichiro Inoue, Hideto Yanagihara
  Advanced Materials Interfaces, 8 (2021) 2101034.
• "Reduced magnetocrystalline anisotropy of CoFe₂O₄ thin films studied by angle-dependent x-ray magnetic circular dichroism"
  Yosuke Nonaka, Yuki K. Wakabayashi, Goro Shibata, Shoya Sakamoto, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Masaaki Tanaka, Ryosho Nakane, and Atsushi Fujimori
  AIP Advances, 11 (2021) 085317.
• "Spin reorientation in tetragonally distorted spinel oxide NiCo₂O₄ epitaxial films"
  Hiroki Koizumi, Ikumi Suzuki, Daisuke Kan, Jun-ichiro Inoue, Yusuke Wakabayashi, Yuichi Shimakawa, and Hideto Yanagihara
  Phys. Rev. B, 104 (2021) 014422.
• "Large Orbital Magnetic Moment and Strong Perpendicular Magnetic Anisotropy in Heavily Intercalated Fe_xTiS₂"
  Goro Shibata, Choongjae Won, Jaewook Kim, Yosuke Nonaka, Keisuke Ikeda, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Arata Tanaka, Sang-Wook Cheong, and Atsushi Fujimori
  J. Phys. Chem. C, 125 (2021) 12929.
• "Anomalous Nernst and Seebeck effects in NiCo₂O₄ films"
  Hiroki Koizumi, Atsushi Hidaka, Takashi Komine, and Hideto Yanagihara
  J. Magn. Soc. Jpn., 45 (2021) 37.
• "Anisotropic Spin Distribution and Perpendicular Magnetic Anisotropy in a Layered Ferromagnetic Semiconductor (Ba,K)(Zn,Mn)₂As₂"
  Shoya Sakamoto, Guoqiang Zhao, Goro Shibata, Zheng Deng, Kan Zhao, Xiancheng Wang, Yosuke Nonaka, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Arata Tanaka, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, and Atsushi Fujimori
  ACS Appl. Electron. Mater., 3 (2021) 789.
• "Bond-length mapping without two-dimensional scanning by means of photoemission electron microscopy-extended X-ray absorption fine structure measurement"
  Masako Suzuki-Sakamaki and Kenta Amemiya
  Jpn. J. Appl. Phys., 59 (2020) 105504.
• "Experimental evidence of orbital ferrimagnetism in CoMnO₃(0001) epitaxial thin film"
  Hiroki Koizumi, Sonia Sharmin, Kenta Amemiya, Masako Suzuki-Sakamaki, Jun-ichiro Inoue, and Hideto Yanagihara
  Phys. Rev. Materials, 3 (2019) 024404.
• "Anisotropic Charge Distribution Induced by Spin Polarization in La_0.6Sr_0.4MnO₃ Thin Films Studied by X-ray Magnetic Linear Dichroism"
  Goro Shibata, Kohei Yoshimatsu, Keisuke Ishigami, Takayuki Harano, Yukio Takahashi, Shoya Sakamoto, Yosuke Nonaka, Toshiharu Kadono, Mitsuho Furuse, Schuichiro Fuchino, Makoto Okano, Jun-ichi Fujihira, Akira Uchida, Kazunori Watanabe, Hideyuki Fujihira, Seiichi Fujihira, Arata Tanaka, Hiroshi Kumigashira, Tsuneharu Koide, and Atsushi Fujimori
  J. Phys. Soc. Jpn., 87 (2018) 114713.
• "Development of high signal-to-background ratio depth-resolved soft X-ray absorption spectroscopy by fluorescence energy selection"
  Masako Suzuki-Sakamaki and Kenta Amemiya
  Jpn. J. Appl. Phys., 57 (2018) 120308.
• "Observation of an electric field-induced interface redox reaction and magnetic modification in GdO_x/Co thin film by means of depth-resolved X-ray absorption spectroscopy"
  Masako Sakamaki and Kenta Amemiya
  Physical Chemistry Chemical Physics, 20 (2018) 20004.
• "Effect of interface NiO layer on magnetism in Fe/BaTiO₃ thin film"
  Masako Sakamaki and Kenta Amemiya
  Jpn. J. Appl. Phys., 57 (2018) 0902B9.
• "Electronic states and possible origin of the orbital-glass state in a nearly metallic spinel cobalt vanadate: An x-ray magnetic circular dichroism study"
  Yosuke Nonaka, Goro Shibata, Rui Koborinai, Keisuke Ishigami, Shoya Sakamoto, Keisuke Ikeda, Zhendong Chi, Tsuneharu Koide, Arata Tanaka, Takuro Katsufuji, and Atsushi Fujimori
  Phys. Rev. B, 97 (2018) 205126.
• "Irradiation effect on magnetic properties of FeRh thin films with energetic C60 cluster ion beam"
  Ryunosuke Soma, Yuichi Saitoh, Masako Sakamaki, Kenta Amemiya, Akihiro Iwase, and Toshiyuki Matsui
  AIP Advances, 8 (2018) 056433.
• "Anisotropic spin-density distribution and magnetic anisotropy of strained La_1−xSr_xMnO₃ thin films: angle-dependent x-ray magnetic circular dichroism"
  Goro Shibata, Miho Kitamura, Makoto Minohara, Kohei Yoshimatsu, Toshiharu Kadono, Keisuke Ishigami, Takayuki Harano, Yukio Takahashi, Shoya Sakamoto, Yosuke Nonaka, Keisuke Ikeda, Zhendong Chi, Mitsuho Furuse, Shuichiro Fuchino, Makoto Okano, Jun-ichi Fujihira, Akira Uchida, Kazunori Watanabe, Hideyuki Fujihira, Seiichi Fujihira, Arata Tanaka, Hiroshi Kumigashira, Tsuneharu Koide & Atsushi Fujimori
  npj Quantum Materials, 3 (2018) 3.
• "Enhanced Anisotropy in Tetragonalized (Cu,Co)Fe₂O₄ Particles via the Jahn–Teller Effect of Cu²⁺ Ions"
  Hawa Latiff, Mikio Kishimoto, Sonia Sharmin, Eiji Kita, Hideto Yanagihara, Takashi Nakagawa
  IEEE Transactions on Magnetics, 53 (2017) 9402304.
• "Large Negative Uniaxial Magnetic Anisotropy in Epitaxially Strained Nickel Ferrite Films"
  Mitsuharu Matsumoto, Sonia Sharmin, Jun-ichiro Inoue, Eiji Kita, Hideto Yanagihara
  IEEE Transactions on Magnetics, 53 (2017) 250364.
• "Magnetic anisotropy of L1₀-ordered FePt thin films studied by Fe and Pt L1_2,3-edges x-ray magnetic circular dichroisms"
  K. Ikeda, T. Seki, G. Shibata, T. Kadono, K. Ishigami, Y. Takahashi, M. Horio, S. Sakamoto, Y. Nonaka, M. Sakamaki, K. Amemiya, N. Kawamura, M. Suzuki, K. Takanashi, and A. Fujimori
  Appl. Phys. Lett., 111 (2017) 142402.
• "Effects of cobalt substitution in L1₀ -(Fe,Co)Pt thin films"
  Shoya Sakamoto, Kumar Srinivasan, Rui Zhang, Oleg Krupin, Keisuke Ikeda, Goro Shibata, Yosuke Nonaka, Zhendong Chi, Masako Sakamaki, Kenta Amemiya, Atsushi Fujimori, and Antony Ajan
  Phys. Rev. B, 96 (2017) 144437.
• "Nanometer-resolution depth-resolved measurement of florescence-yield soft x-ray absorption spectroscopy for FeCo thin film"
  Masako Sakamaki and Kenta Amemiya
  Rev. Sci. Instrum., 88 (2017) 083901.