Large thermoelectric power in low-dimensional transition-metal oxides

2012 Fiscal Year Final Research Report

• Project/Area Number: 22560676
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: National Institute for Materials Science
• Principal Investigator: ISOBE Masaaki 独立行政法人物質・材料研究機構, 超伝導物性ユニット, グループリーダー (10354309)
• Co-Investigator(Kenkyū-buntansha): ARAI Masao 独立行政法人物質・材料研究機構, 理論計算科学ユニット, 主幹研究員 (40222723)
• Project Period (FY): 2010 – 2012
• Keywords: 熱電材料 / 遷移金属酸化物 / 強相関電子系 / 磁性 / 計算物理

Research Abstract

We have studied structural and physical properties of the novel 1-dimensional cobalt-oxide system Ca1-xNaxCo2O4. It was found that the heavily Na-substituted phases with x = 0.4 - 0.6 can exhibit metallic conductivity and unusually large thermoelectric power which is comparable to that in a layered cobalt oxide Ca3Co4O9. A possible mechanism of the large thermoelectric power is discussed from the viewpoint of the band structure and the strong electronic correlation in the 3d electron system.

Research Products

• [Journal Article] Orbital switching in a frustrated magnet (2012)
  • Author(s): Hiroyuki Yoshida, Jun-ichi Yamaura, Masaaki Isobe, Yoshihiko Okamoto, Goran J. Nilsen, and Zenji Hiroi
  • Journal Title: Nature commun. Volume: 3 Pages: 1-5
  • Peer Reviewed
• [Journal Article] β-Vesignieite BaCu3V2O8(OH)2: a structurally perfect S = 1/2 kagome antiferromagnet (2012)
  • Author(s): Hiroyuki Yoshida, Yuichi Michiue, Eiji Takayama-Muromachia, and Masaaki Isobe
  • Journal Title: J. Mater. Chem. Volume: 22 Pages: 18793-18796
  • Peer Reviewed
• [Journal Article] Partially disordered state and spin-lattice coupling in an S = 3/2 triangular lattice antiferromagnet Ag_2CrO_2 (2012)
  • Author(s): M. Matsuda, H. Yoshida, M. Isobe, C. de la Cruz, and R. S. Fishman
  • Journal Title: Phys. Rev. B Volume: 85
  • Peer Reviewed
• [Journal Article] Spin-Orbit Mott State in the Novel Quasi-2D Antiferromagnet Ba_2IrO_4 (2012)
  • Author(s): M. Isobe, H. Okabe, E. Takayama-Muromachi, A. Koda, S. Takeshita, M. Hiraishi, M. Miyazaki, R. Kadono, Y. Miyake, and J. Akimitsu
  • Journal Title: J. Phys: Conf. Series Volume: 40 Pages: 1-4
  • Peer Reviewed
• [Journal Article] Magnetic ordering in spin-orbit Mott insulator Ba_2IrO_4 probed by μSR (2012)
  • Author(s): H. Okabe, M. Isobe, E. Takayama-Muromachi, A. Koda, S. Takeshita, M. Hiraishi, M. Miyazaki, R. Kadono, Y. Miyake, and J Akimitsu
  • Journal Title: J. Phys: Conf. Series Volume: 400 Pages: 1-4
  • Peer Reviewed
• [Journal Article] Ba_2IrO_4: A spin-orbit Mott insulating quasi-two-dimensional antiferromagnet (2011)
  • Author(s): H. Okabe, M. Isobe, E. Takayama-Muromachi, A. Koda, S. Takeshita, M. Hiraishi, M. Miyazaki, R. Kadono, Y. Miyake, and J. Akimitsu
  • Journal Title: Phys. Rev, B Volume: 83 Pages: 1-8
  • Peer Reviewed
• [Journal Article] Pressure-induced metal-insulator transition in the spin-orbit Mott insulator Ba_2IrO_4 (2011)
  • Author(s): H. Okabe, N. Takeshita, M. Isobe, E. Takayama-Muromachi, T. Muranaka, and J. Akimitsu
  • Journal Title: Phys. Rev. B Volume: 84 Pages: 1-6
  • Peer Reviewed
• [Journal Article] Novel S = 3/2 Triangular Antiferromagnet Ag_2CrO_2 with Metallic Conductivity (2011)
  • Author(s): Hiroyuki YOSHIDA, Eiji TAKAYAMA-MUROMACHI, and Masaaki ISOBE
  • Journal Title: J. Phys. Soc. Jpn. Volume: 80 Pages: 1-4
  • Peer Reviewed
• [Journal Article] Crystal structure and magnetic properties of 6H-SrMnO_3 (2011)
  • Author(s): Alexei A. Belik, Yoshitaka Matsushita, Yoshio Katsuya, Masahiko Tanaka, Taras Kolodiazhnyi, Masaaki Isobe, and Eiji Takayama-Muromachi
  • Journal Title: Phys. Rev. B Volume: 84 Pages: 1-6
  • Peer Reviewed
• [Journal Article] Phase composition and magnetic properties of niobium-iron codoped TiO_2 nano particles synthesized in Ar/O_2 radio-frequency thermal plasma (2011)
  • Author(s): Chenning Zhang, MasashiIkeda, Masaaki Isobe, Tetsuo Uchikoshi, Ji-Guang Li, Takayuki Watanabe, Takamasa Ishigaki
  • Journal Title: J. Solid State Chem. Volume: 184 Pages: 2525-2532
  • Peer Reviewed
• [Journal Article] Structural studies of a mixed-valence state in the incommensurate composite crystal Sr_1.261CoO_3 (2010)
  • Author(s): Masaaki Isobe, Hiroyuki Yoshida, Eiji Takayama Muromachi, and Kenji Ohoyama
  • Journal Title: Sci. Tech. Adv. Mater Volume: 11 Pages: 1-13
  • Peer Reviewed
• [Journal Article] Muon spin relaxation study of misfit-layered cobalt dioxide [Ca_0.85OH]1.16RS[CoO_2] (2010)
  • Author(s): Martin Mansson, Yutaka Ikedo, Hiroshi Nozaki, Jun Sugiyama, Peter L. Russo, Daniel Andreica, Mitsuyuki Shizuya, Masaaki Isobe, and Eiji Takayama-Muromachi
  • Journal Title: Solid State Commun. Volume: 15 Pages: 307-310
  • Peer Reviewed
• [Journal Article] _59Co NMR study on local magnetic properties of Ca_1-xNaxCo_2O_4 (2010)
  • Author(s): Tsuyoshi Takami, Masayuki Itoh, Masaaki Isobe, Masao Arai, Tetsuya Kawashima, and Eiji Takayama-Muromachi
  • Journal Title: J. Phys.: Conference Series Volume: 200 Pages: 1-4
  • Peer Reviewed
• [Presentation] スピン軌道モット絶縁体Ba2IrO4の磁化率 (2013)
  • Author(s): 磯部雅朗、岡部博孝、室町英治、秋光純
  • Organizer: 日本物理学会第68回年次大会
  • Place of Presentation: 広島大(東広島市)
  • Year and Date: 20130326-29
• [Presentation] Thermoelectric Properties of the Novel Quasi-1D Cobalt Oxides (Ca,Na)Co_2O_4 (2012)
  • Author(s): M. Isobe, M. Arai, T. Kawashima, E. Takayama-Muromachi, and A. Irizawa
  • Organizer: IUMRS-International Conference on Electronic Materials 2012
  • Place of Presentation: Yokohama
  • Year and Date: 20120923-28
• [Presentation] K_2NiF_4-type iridates: unconventional magnetic behabior just like a high-Tc cuprate (2012)
  • Author(s): Masaaki Isobe, Hirotaka Okabe, E. Takayama-Muromachi, and Jun Akimitsu
  • Organizer: Materials and Mechanism of Superconductivity 2012
  • Place of Presentation: Washington DC, USA
  • Year and Date: 20120729-0803
• [Presentation] Magnetic states in quasi-2-D iridium oxides with large spin-orbit coupling (2012)
  • Author(s): Masaaki Isobe, Hirotaka Okabe, and Jun Akimitsu
  • Organizer: The19th International Conferenceon Magnetism with Strongly Correlated Electron Systems (ICM/SCES)
  • Place of Presentation: Busan, Korea
  • Year and Date: 20120708-13
• [Presentation] Magnetic states and M-I transition in the novel quasi-2-D iridate Ba2IrO4 with large spin-orbit coupling (2012)
  • Author(s): Masaaki Isobe
  • Organizer: International Workshop on Mott physics beyond the Heisenberg model 2012
  • Place of Presentation: Lausanne, Switzerland
  • Year and Date: 20120625-28
• [Presentation] 新規スピン・軌道モット絶縁体Ba2IrO4の構造と磁性 (2011)
  • Author(s): 磯部雅朗、岡部博孝、室町英治、秋光純
  • Organizer: 日本物理学会2011年秋季大会
  • Place of Presentation: 富山大学五幅キャンパス(富山市)
  • Year and Date: 20110921-24
• [Presentation] Spin-Orbit Mott State in the Novel Quasi-2D Iridate Ba_2IrO_4 (2011)
  • Author(s): M. Isobe, H. Okabe, E. Takayama-Muromachi, A. Koda, S. Takeshita, M. Hiraishi, M. Miyazaki, R. Kadono, Y. Miyake, and J. Akimitsu
  • Organizer: International Conference on Strongly Correlated Electron Systems 2011
  • Place of Presentation: Cambridge, England
  • Year and Date: 20110831-0903
• [Presentation] Transport Properties of the Novel Quasi-1D Cobalt Oxide (Ca,Na)Co_2O_4 (2011)
  • Author(s): M. Isobe, T. Kawashima, M. Arai, E. Takayama-Muromachi, and A. Irizawa
  • Organizer: 26th International Conference on Low Temperature Physics (LT26)
  • Place of Presentation: Beijing, China
  • Year and Date: 20110810-17
• [Presentation] Spin-Orbit Mott State in the Novel Quasi-2D Antiferromagnet Ba_2IrO_4 (2011)
  • Author(s): M. Isobe, H. Okabe, E. Takayama-Muromachi, A. Koda, S. Takeshita, M. Hiraishi, M. Miyazaki, R. Kadono, Y. Miyake, and J. Akimitsu
  • Organizer: 26th International Conference on Low Temperature Physics (LT26)
  • Place of Presentation: Beijing, China
  • Year and Date: 20110810-17
• [Presentation] Ba_2IrO_4:新規スピン・軌道モット絶縁性擬二次元反強磁性体 (2011)
  • Author(s): 磯部雅朗、岡部博孝、室町英治、秋光純
  • Organizer: 日本物理学会第66回年次大会
  • Place of Presentation: 新潟大学(新潟県)
  • Year and Date: 20110325-28
• [Presentation] Sr_2Ir_1-xRh_xO_4におけるスピン・軌道相互作用と磁気相関 (2010)
  • Author(s): 磯部雅朗、吉田紘行、室町英治、入澤明典
  • Organizer: 物理学会2010年秋季大会
  • Place of Presentation: 大阪府立大学(大阪府)
  • Year and Date: 20100923-26
• [Presentation] Transport properties of Na-substituted CaCo_2O_4 (2010)
  • Author(s): Masaaki Isobe, Hiroyuki Yoshida, Makoto Tachibana, Tetsuya Kawashima, Masao Arai, Eiji Takayama-Muromachi, Akinori Irizawa
  • Organizer: International Conference on Thermoelectrics (ICT2010)
  • Place of Presentation: Renaissance Shanghai Zhongshan Park Hotel, Shanghai (China)
  • Year and Date: 20100530-0603
• [Remarks]
  • URL: http://www.nims.go.jp/group/g_srongly-correlated-materials/index.html