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Phonon Transport Properties and Magnetic Transition in Perovskite Cobaltites

Research Project

Project/Area Number 14550661
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Inorganic materials/Physical properties
Research InstitutionIWATE UNIVERSITY

Principal Investigator

FUJISHIRO Hiroyuki  IWATE UNIV., Facul.Eng., Associate Prof., 工学部, 助教授 (90199315)

Co-Investigator(Kenkyū-buntansha) IKEBE Manabu  IWATE UNIV., Facul.Eng., Professor, 工学部, 教授 (40005955)
Project Period (FY) 2002 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
KeywordsCobaltite Oxides / Spin Transition / Thermal Conductivity / Jahn-Teller Ions / Thermoelectric Materials / Phanon Scattering / Thermoelectric Power / Substitution Effect / 超巨大磁気抵抗 / 熱拡散率 / 強磁性転移
Research Abstract

As recent revived studies on perovskite-based oxides have confirmed, RE_<1-X>A_XMO_3-type crystals (RE=rare earth ions, M=Mn, Co) undergo a variety of phase transitions which originate from the interplay and competition of various physical interactions. There are many results of electric, magnetic and crystallographic properties in these systems, however, the thermal (phonon) transport properties such as the thermal conductivity κ, thermal diffusivity α, and thermal dilatation dL/L have not been reported. In this study, we systematically measured these thermal transport properties of La_<1-X>AE_XCoO_3 (AE=Sr, Ca, Ba) crystals and investigated the phonon scattering mechanisms. The remarkable results are as follows ;
(1)The thermal conductivity κ of the La_<1-X>Sr_XCoO_3 (X>0.2) system slightly enhances below the ferromagnetic transition temperature T_c, which is clearly understood on the basis of the increase in the electronic thermal conductivity κ_e. These results are contrast to those in La_<1-X>Sr_XMnO_3 (X>0.2), in which the relaxation of the Jahn-Teller (JT) distortion takes place below T_c.
(2)The thermal conductivity κ of LaCoO_3 is markedly enhanced at 30K, however, the peak drastically decreases due to the substitution by the Sr^<2+> ions for the La^<3+> with 0.5% or by the Cu^<2+> and Ni^<2+> ions for the Co^<3+> with only 2%. It was found that the introduction of the Co^<4+> JT ions by the substitution seriously influences to the phonon transport.
(3)The La_<1-X>Sr_XCoO_3 (0.1<X<0.15) system shows a promising candidate for the p-type thermoelecteric material around room temperatures, which is the phase boundary between the antiferromagnetic or spin-glass insulator and the ferromagnetic metal region.

Report

(3 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • Research Products

    (16 results)

All Other

All Publications (16 results)

  • [Publications] K.Suzuki, H.Fujishiro, Y.Kashiwada, Y.Fujine, M.Ikebe: "Magnetic, electrical and thermal properties of La_<0.80>Sr_<0.20>(Mn_yCo_<1-y>)O_3"Physica B. 329-333. 922-923 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] H.Fujishiro, Y.Fujine, Y.Kashiwada, M.Ikebe, J.Hejtmanek: "Enhanced Thermoelectric Properties at X〜0.1 in La_<1-X>Sr_XCoO_3 and La_<1-X>Sr_X(Co_<1-Y>M_Y)O_3(M=Cr, Cu)"Proceedings of 21th International Conference on Thermoelectrics(ICT '03 )IEEE. 235-238 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] H.Fujishiro, Y.Fujine, J.Hejtmanek, D.Sedmidubsky, A.Maigan, C.Martin: "Search for p-type oxide thermoelectrics -- cobaltites"Proceedings of 21th International Conference on Thermoelectrics(ICT '03)IEEE. 192-195 (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Y.Fujine, H.Fujishiro, K.Suzuki, Y.Kashiwada, M.Ikebe: "Magnetism and thermoelectricity in La_<0.8>Sr_<0.2>Co_<1-Z>M_ZO_3(M : 3d transition metal)"J.Mag.Mag.Mat.. (to be published). (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] J.Hejtmanek, Z.Jirak, K.Knizek, M.Marysko M.Veverka, H.Fujishiro: "Magnetism, structure and transport of Y_<1-X>Ca_XCoO_3 and La_<1-X>Ba_XCoO_3"J.Mag.Mag.Mat.. (to be published). (2004)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Suzuki, H.Fujishiro, Y.Kashiwada, Y.Fujine, M.Ikebe: "Magnetic, electrical and thermal properties of La_<0.80>Sr_<0.20>(Mn_yCo_<1-y>)O_3."Physica B. 329-333. 922-923 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] H.Fujishiro, Y.Fujine, Y.Kashiwada, M.Ikebe, J.Hejtmanek: "Enhanced Thermoelectric Properties at X〜0.1 in La_<1-X>Sr_XCoO_3 and La_<1-X>Sr_X(Co_<1-Y>M_Y)O_3 (M=Cr, Cu)"Proc.21th Int.Conf.Thermoelectrics (ICT2003). 235-238 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] H.Fujishiro, Y.Fujine, J.Hejtmanek, D.Sedmidubski, A.Maigan, C.Martin: "Search for p-type oxide thermoelectrics --cobaltites--"Proc.21th Int.Conf.Thermoelectrics (ICT2003). 192-195 (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Y.Fujine, H.Fujishiro, K.Suzuki, Y.Kashiwada, M.Ikebe: "Magnetism and thermoelectricity in La_<0.8>Sr_<0.2>Co_<1-Z>M_ZO_3."J.Mag.Mag.Mat.. (in press). (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] J.Hejtmanek, Z.Jirak, K.Knizek, M.Marysko, M.Veverka, H.Fujishiro: "Magnetism, structure and transport in Y_<1-X>Ca_XCoO_3 and La_<1-X>Ba_XCoO_3."J.Mag.Mag.Mat.. (in press). (2004)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Suzuki, H.Fujishiro, Y.Kashiwada, Y.Fujine, M.Ikebe: "Magnetic, electrical and thermal properties of La_<0.80>Sr_<0.20>(Mn_yCo_<1-y>)O_3"Physica B. 329-333. 922-923 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] H.Fujishiro, Y.Fujine, Y.Kashiwada, M.Ikebe, J.Hejtmanek: "Enhanced Thermoelectric Properties at X〜0.1 in La_<1-X>Sr_X(Co_<1-Y>M_Y)O_3 (M=Cr, Cu)"Proceedings of 21th International Conference on Thermoelectrics (ICT '03) IEEE. 235-238 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] H.Fujishiro, Y.Fujine, J.Hejtmanek, D.Sedmidubsky, A.Maigan, C.Martin: "Search for p-type oxide thermoelectrics -- cobaltites"Proceedings of 21th International Conference on Thermoelectrics (ICT '03) IEEE. 192-195 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] Y.Fujine, H.Fujishiro, K.Suzuki, Y.Kashiwada, M.Ikebe: "Magnetism and thermoelectricity in La_<0.8>Sr_<0.2>Co_<1-Z>M_ZO_3 (M : 3d transition metal)"J.Mag.Mag.Mat.. (to be published). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] J.Hejtmanek, Z.Jirak, K.Knizek, M.Marysko, M.Veverka, H.Fujishiro: "Magnetism, structure and transport of Y_<1-X>Ca_XCoO_3"J.Mag.Mag.Mat.. (to be published). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Suzuki, H.Fujishiro, Y.Kashiwada, Y.Fujine, M.Ikebe: "Magnetic, electrical and thermal properties of La_<0.80>Sr_<0.20>(Mn_<1-y>CO_y)O_3"PHYSICA B. (出版予定). (2003)

    • Related Report
      2002 Annual Research Report

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Published: 2002-04-01   Modified: 2016-04-21  

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