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1994 Fiscal Year Final Research Report Summary

Search for Regenerative Materials with Large Specific Heat Based on Rare Earth-Manganese Compounds

Research Project

Project/Area Number 04555155
Research Category

Grant-in-Aid for Developmental Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Physical properties of metals
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

SHIGA Masayuki  KYOTO UNIVERSITY,DEPARTMENT OF MATERIALS SCIENCE AND PROFESSOR, 工学部, 教授 (30026025)

Co-Investigator(Kenkyū-buntansha) NAKAMURA Hiroyuki  KYOTO UNIVERSITY,DEPARTMENT OF MATERIALS SCIENCE AND INSTRUCTOR, 工学部, 助手 (00202218)
WADA Hirofumi  KYOTO UNIVERSITY,DEPARTMENT OF MATERIALS SCIENCE AND ASSOCIATE PROFESSOR, 工学部, 助教授 (80191831)
Project Period (FY) 1992 – 1994
KeywordsMagnetic regenerative materials / Rare earth-Mn compound / Low temperature specific heat / Magnetic entropy / Crystal field / Spin fluctuation
Research Abstract

In recent years, much attention has been paid to rare earth (R) compounds with large specific heat at low temperatures as magnetic regenerative materials, because of the spread of small cryocooler and superconducting magnets. In the RMn_2 compounds, both R and Mn have large magnetic moments in spite of their low magnetic ordering temperatures. We have examined low temperature specific heat and related properties of this system in order to develop new regenerative materials. The following results were obtained :
(1) In the case of Al substitution for Mn, the system shows spin glass at low temperatures. The specific heat and entropy become very large above 50K,but they are not enhanced at low temperatures.
(2) On the other hand, in the compounds with smaller atomic distance such as HoMn_2 and ErMn_2, most of Mn atoms are nonmagnetic. Large spin fluctuations were observed in these compounds, which enhance electronic specific heat at low temperatures.
(3) The crystal field is also an important factor for large specific heat. The analyzes of crystal field were developed and were successfully applied to RCo_2 and RMn_2Ge_2 compounds.
Base on these results, we conclude that Cu and Ni substitution for RMn_2 is a candidate for new regenerative materials, which is under investigation. We also found that a suitable material is expected for(Dy-Er)Bi compounds.

  • Research Products

    (22 results)

All Other

All Publications (22 results)

  • [Publications] M. Shiga: "Spin Liquid Behavior of Highly Frustrated Y ( Sc ) Mn_2 and Effects of Nonmagnetic Impurity" J. Phys Soc. Japan. 62. 1329-1336 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Nakamura: "Anomalous Magnetism of the Frustrated Compound GdInCu_4" Physica B. 186-188. 633-635 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Shiga: "Magnetic Ordering and Frustration in Itinerant Systems: RMn_2" J. Magn. Magn. Mater.129. 17-25 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Nakamura: "Magnetic and Transport Properties in the Low-carrier System Gd_<1-x>Lu_xInCu_4" J. Phy. Condens. Matter. 6. 6801-6813 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Wada: "Antiferromagnetic Properties of EuAl_2" Physica B. 193. 25-30 (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Wada: "Low Temperature Specific Heat of DyBi and ErBi" J. Alloys and Compounds. 218. 73-76 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Nakamura: "Nuclear Magnetic Relaxation in C14 YMn_2" J. Magn. Magn. Mater.(印刷中). (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Imai: "Calorimetric Study on Magnetism of ErCo_2" J. Magn. Magn. Mater.(印刷中). (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H. Imai: "Effects of Spin Fluctuations on the Specific Heat in YMn_2 and Y_<0.97>Sc_<0.03>Mn_2" J. Phy. Soc. Japan. (印刷中). (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Moriwaki: "Observation of Magnetic Mn in Cubic and Hexagonal HoMn_2" J. Magn. Magn. Mater.(印刷中). (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Shiga: "Magnetic and Thermal Properties of TbMn_2 and Tb(Mn_<1-X>)_2" J. Magn. Magn. Mater.(印刷中). (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Shiga: "Spin Liquid Behavior of Highly Frustrated Y (Sc) Mn_2 and Effects of Nonmagnetic Impurity" J.Phys Soc.Japan. vol.62. 1329-1336 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Nakamura: "Anomalous Magnetism of the Frustrated Compound GdInCu_4" Physica B. vol.186-188. 633-635 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Shiga: "Magnetic Ordering and Frustration in Itinerant Systems : RMn_<2S>" J.Magn.Magn.Mater.vol.129. 17-25 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Nakamura: "Magnetic and Transport Properties in the Low-carrier System Gd_<1-x>Lu_xInCu_4" J.Phys.Condens.Matter. vol.6. 6801-6813 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Wada: "Antiferromagnetic Properties of EuAl_2" Physica B. vol.193. 25-30 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Wada: "Low Temperature Specific Heat of DyBi and ErBi" J.Alloys and Compounds. vol.218. 73-76 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Nakamura: "Nuclear Magnetic Relaxation in C14 YMn_2" to be published in J.Magn.Magn.Mater.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Imai: "Calorimetric Study on Magnetism of ErCo_2" to be published in J.Magn.Magn.Mater.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Imai: "Effects of Spin Fluctuations on the Specific Heat in YMn_2 and Y_<0.97>Mn_2" to be published in J.Phys.Soc.Japan.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Moriwaki: "Observation of Magnetic Mn in Cubic and Hexagonal HoMn_2" to be published in J.Magn.Magn.Mater.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Shiga: "Magnetic and Thermal Properties of TbMn_2 and Tb(Mn_<1-x>Al_x)_2" to be published in J.Magn.Magn.Mater.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1996-04-15  

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