Colossal Magnetocaloric Effect of Mn-based Compounds under Pressure

2008 Fiscal Year Final Research Report

• Project/Area Number: 18340107
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Kyushu University
• Principal Investigator: WADA Hirofumi Kyushu University, 大学院・理学研究院, 教授 (80191831)
• Co-Investigator(Renkei-kenkyūsha): MITSUDA Akihiro 九州大学, 大学院・理学研究院, 准教授 (20334708)
• Project Period (FY): 2006 – 2008
• Keywords: 磁性

Research Abstract

MnAsは室温で巨大磁気熱量効果を示す物質である. 最近ブラジルのグループによってMnAsに圧力を加えると磁気熱量効果が極めて大きくなることが報告された. 本研究ではこの超巨大磁気熱量効果の検証を行った. その結果超巨大磁気熱量効果は測定の問題で生じた現象で本質的な性質でないことが明らかになった. また, 超巨大磁気熱量効果の起源といわれている格子のエントロピー変化を定量的に評価することに成功した, その値は全エントロピー変化の高々10%であることも明らかになった.

Research Products

• [Journal Article] Pressure dependence of magnetic entropy change and magnetic transition in MnAs_<1-x>Sb_x (2009)
  • Author(s): H. Wada, S. Matsuo, and A. Mitsuda
  • Journal Title: Phys. Rev. B Vol.79, 092407 Pages: 4
• [Journal Article] Imada Electronic and Magnetic States of Mn_<2.97>Co_<0.03>GaC Studied by Soft X-ray Imada Electronic and Magnetic States of Mn2.97Co0.03GaC Studied by Soft X-ray (2008)
  • Author(s): A. Matsumoto, M. Tsunekawa, S. Suga, H. Wada, T. Muro, T. Nakamura and S.
  • Journal Title: Jpn.J.Appl.Phys Vol.47 Pages: 1597-1569
• [Journal Article] Giant Magnetocaloric Effect and Soft-mode Magneto-structural Phase Transition in MnAs EPL (2008)
  • Author(s): J. D. Zou, H. Wada, B. G. Shen, J. R. Sun and W. Li
  • Journal Title: Vol.81, 47001 Pages: 4
• [Journal Article] Soft X-ray magnetic circular dichroism of Ce(Fe_<0.8>Co_<0.2>)_2 (2007)
  • Author(s): M. Tsunekawa, S. Imada, , A. Matsumoto, A. Yamasaki, H. Fujiwara, S. Suga, B. Schmid, H. Higashimichi, T. Nakamura, T. Muro and H. Wada
  • Journal Title: AIP Conference Proceedings Vol.879 Pages: 1703-1706
• [Journal Article] Development of Room Temperature Magnetic Refrigerator overall plan Proc. 2nd Int. Conf (2007)
  • Author(s): N. Hirano, S. Nagaya, T. Okamura, T. Kawanami and H. Wada
  • Journal Title: on Magnetic Refrigeration at Room Temperature Pages: 281-287
• [Journal Article] Direct measurements of magnetocaloric effects of Mn_<1+δ>As_<1-x>Sb_x (2007)
  • Author(s): H. Wada, T. Asano, M. Ilyn and A. M. Tishin
  • Journal Title: J. Magn. Magn. Mater. Vol.310 Pages: 2811-2812
• [Journal Article] 磁気熱量効果と磁気冷凍材料 (2006)
  • Author(s): 和田裕文
  • Journal Title: 熱測定 第33巻第3号 Pages: 98-103
• [Journal Article] Magnetic entropy change of itinerant electron metamagnetic system Co(S_<1-x>Se_x)_2 (2006)
  • Author(s): H. Wada, A. Mitsuda, and K. Tanaka
  • Journal Title: Phys, Rev. B Vol.74, 214407 Pages: 5
• [Journal Article] First-order phase transition at the Curie temperature in MnAs and MnAs_<0.9>Sb_<0.1> (2006)
  • Author(s): F. Ishikawa, K. Koyama, K. Watanabe, T. Asano and H. Wada
  • Journal Title: J. Phys. Soc. Japan Vol.75 No.8, 084604 Pages: 6
• [Journal Article] Effect of heat treatment on the magnetic phase transition and magnetocaloric properties of Mn_<1+δ>As_<1-x>Sb_x (2006)
  • Author(s): H. Wada, C. Funaba and T. Asano
  • Journal Title: Mater. Trans Vol.47 No.3 Pages: 486-491
• [Presentation] Pressure Dependence of Magnetocaloric Effect of MnAs_<1-x>Sb_x and La(Fe_<1-x>Si_x)_<13> Delft Days on Magnetocalorics (2008)
  • Author(s): H. Wada
  • Place of Presentation: TU Delft(オランダ)
  • Year and Date: 2008-10-31
• [Presentation] Co(S, Se)_2の高圧下磁気熱量効果 (2008)
  • Author(s): 佐田國修, 光田暁弘, 和田裕文
  • Organizer: 日本物理学会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-21
• [Presentation] La(Fe_xSi_<1-x>)13の高圧下における磁気熱量効果 (2008)
  • Author(s): 貞松康史, 光田暁弘, 和田裕文
  • Organizer: 日本物理学会
  • Place of Presentation: 岩手大学
  • Year and Date: 2008-09-21
• [Presentation] Possible Magnetic Refrigerant Materials near Room Temperature : La(Fe_xCoySi_<1-x-y>) (2007)
  • Author(s): H. Wada
  • Organizer: 13 International Conference on Magneto- Science
  • Place of Presentation: Int. Conf. Center, Hiroshima(広島市)
  • Year and Date: 2007-11-13
• [Presentation] MnAsの磁気熱量効果に及ぼす圧力効果 (2007)
  • Author(s): 松尾省吾, 光田暁弘, 和田裕文
  • Organizer: 日本物理学会
  • Place of Presentation: 北海道大学
  • Year and Date: 2007-09-22
• [Presentation] Shock Compaction of MnAs_<1-x>Sb_x Powder using Underwater Shock Wave Proc (2007)
  • Author(s): Y. K. Kim, H. Wada and S. Itoh
  • Organizer: 15th APS Topical Conference on Shock Compression of Condensed Matter
  • Place of Presentation: Hawaii
  • Year and Date: 2007-06-26
• [Presentation] Development of Room Temperature Magnetic Refrigerator-overall plan (2007)
  • Author(s): N. Hirano, S. Nagaya, T. Okamura, T. Kawanami and H. Wada
  • Organizer: 2^<nd> IIF-IIR Int. Conf. Magnetic Refrigeration at Room Temperature
  • Place of Presentation: Portoroz(スロベニア)
  • Year and Date: 2007-04-11