1999 Fiscal Year Annual Research Report

ダブル・ペロブスカイトにおける新規機能の創出

Research Project

Project/Area Number	11305002
Research Category	Grant-in-Aid for Scientific Research (A)
Research Institution	Tokyo Institute of Technology
Principal Investigator	山内尚雄東京工業大学, 応用セラミックス研究所, 教授 (50271581)
Co-Investigator(Kenkyū-buntansha)	谷山智康東京工業大学, 大学院・総合理工学研究科, 助手 (10302960) 末松久幸東京工業大学, 応用セラミックス研究所, 助手 (30222045) 山崎陽太郎東京工業大学, 大学院・総合理工学研究科, 教授 (50124706)
Keywords	ダブル・ペロブスカイト / Verwey型転移 / 酸素量 / 低酸素分圧下合成 / 超高酸素分圧下熱処理法 / 磁気異常
Research Abstract	ハーフメタルであることが示唆されている、"0112"ダブルペロブスカイト型構造を有する銅鉄酸化物の合成と磁気特性の観察を行った。原料粉末を金属ゲッターと共に石英管で封入、加熱することにより、BaSm(Cu_<0.5+x>Fe_<0.5-x>)_2O_<5+d>を、10-3〜10-16barの低酸素分圧下で合成した。この結果、x=-0.1と-0.4に固溶限界があることが分かった。X=0.0の試料をメスバウアー分光により分析したところ、200-240℃以上ではFeの価数は+2.5であるが、それ以上では+2と+3に分離することが分かった。この温度で、既知の磁化の飛びに加えて、電気抵抗率の急激な上昇がみられることが分かった。この結果から、マグネタイトのVerwey転位に似ている現象が起こっていることが分かった。酸素量5+dを変えたところ、酸素量の増加に伴い磁化の飛びがベル型に変わり、ある酸素量で最大値をもつことが分かった。これに伴い転位温度がある酸素量で最低となることが判明した。これらは微視的な歪みと係わっている可能性があるがその本質は分かっていない。 BaRE(Cu_<0.5>Fe_<0.5>)_2O_<5+d>(RE=希土類元素)のREと酸素量を変えた試料を、超高酸素圧下熱処理法を用いることによって作製した。その結果最大5+d=5.45まで酸素量を増加させた試料を作製した。RE=Prの場合、200K付近での磁気異常があることがわかった。この温度以下では磁化の磁場依存性のヒステリシスと、零磁場冷却と磁場中冷却した場合磁化の差がみられ、これらは磁気異常が起こる温度でほぼ消失していた。これらはスピンのフラストレーションまたは何らかのスピンの相転移によって起こることが示唆された。

Research Products
(18 results)

All Other

All Publications (18 results)

[Publications] J.Nakamura: "Iron Mixed-valence Compounds, BaSm(Cu_<0.5+x>Fe_<0.5-x>)_2O_<5+δ>.I: Synthesis and Chemical Characterization"Physica C. (In press). (2000)
[Publications] J.Linden: "Iron Mixed-valence Compounds, BaSm(Cu_<0.5+x>Fe_<0.5-x>)_2O_<5+δ>.II: The Fe^<2.5+> State and Magnetic Properties"Physica C. (In press). (2000)
[Publications] M.Kochi: "Magnetic Properties, Oxygen Content and Metal Valences in BaRE(Cu_<0.5> Fe_<0.5>)_2O_<5+δ> with RE=Lu, Yb, Y, Eu, Nd and Pr"Physica C. (In press). (2000)
[Publications] H.Yamauchi: "Water-containing Phases Derived from "02(n-1)n" Superconductors. I: Novel 02(n-1)n Homologous Series in the Ba-Ca-Cu-O System and the Derivative Series"Physica C. (In press). (2000)
[Publications] H.Yamauchi: "Water-containing Phases Derived from "02(n-1)n" Superconductors. II: Derivative of the Sr_2Ca_2Cu_3O_<8+δ>(0^<(Sr)>223) Phase"Physica C. (In press). (2000)
[Publications] H.Suematsu: "A Possible Cause of Peak Effect in Y-Ba-Cu-O Melt-Grown Bulks: Modulation in Oxygen Distribution"Physica C. (In press). (2000)
[Publications] M.Karppinen: "Oxygen Non-stoichiometry and Hole Distribution in Multi-layered Copper Oxides: Understanding of the Magnetic Irreversibility Characteristics"Physica C. (In press). (2000)
[Publications] T.Akao: "Irreversibility-field Enhancement by Optimizing Hole Density Distribution in the Hg-1212 Superconductor"Physica C. (In press). (2000)
[Publications] Y.Takahama: "Dependence of Peak Effect on Particle Size Distribution in Superconducting SmBa_2Cu_3O_<7-δ> Powder Samples"Physica C. (In press). (2000)
[Publications] T.Nakane: "Effects of Sr Substitution on the Magnetic-field Irreversibility in Superconductive Cu(Ba_<1-y>Sr_y)_2YbCu_2O_<6+z>;"Physica C. (In press). (2000)
[Publications] H.Yamauchi: "Stabilization and Oxidation-State Control of Novel Superconductive and Related Multi-Layered Copper Oxides"Superconductor Science and Technology. (In press). (2000)
[Publications] H.Suematsu: "Microstructural Cause of the Peak Effect in Superconducting Y-Ba-Cu-O Melt-Grown Bulks"J. Low Temp. Phys.. 117. 843-847 (1999)
[Publications] H.Yamauchi: "Carrier Distribution for Tailoring Superconducting Properties of Layered Cuprates; Journal of Low Temperature Physic"J.Low Temp.Phys.. 117. 813-822 (1999)
[Publications] M.Karppinen: "Superconducting Cuprates with Charge Reservoir Consisting of either Peroxide-Type Oxygen or H_2O"J. Low Temp. Phys.. 117. 843-847 (1999)
[Publications] K.Peitola: "Oxygen Stoichiometry in BaRE(Cu_<0.5>Fe_<0.5>)_2O_<5+δ> Compounds with Perovskite or Double Perovskite Structure"J. Low Temp. Phys.. 117. 861-865 (1998)
[Publications] T.Akao: "Peak Effect Caused by Compositional Modulation in Superconducting (Hg,Pb)(Ba,Sr)-1223 Single Crystal"J. Low Temp. Phys.. 117. 927-931 (1999)
[Publications] M.Karppinen: "Control of the Charge Inhomogeneity and High-T_c Superconducting Properties in Homologous Series of Multi-Layered Copper Oxides"Materials Science & Engineering Reports. 26. 59-96 (1999)
[Publications] H.Yamauchi: "The Peak Effect in High T_c Superconductors"Proceedings of 2^<nd> International Symposium on Electronic Component Material. 81-86 (1999)

1999 Fiscal Year Annual Research Report

ダブル・ペロブスカイトにおける新規機能の創出

Principal Investigator

山内 尚雄 東京工業大学, 応用セラミックス研究所, 教授 (50271581)

Research Products

[Publications] J.Nakamura: "Iron Mixed-valence Compounds, BaSm(Cu_<0.5+x>Fe_<0.5-x>)_2O_<5+δ>.I: Synthesis and Chemical Characterization"Physica C. (In press). (2000)

[Publications] J.Linden: "Iron Mixed-valence Compounds, BaSm(Cu_<0.5+x>Fe_<0.5-x>)_2O_<5+δ>.II: The Fe^<2.5+> State and Magnetic Properties"Physica C. (In press). (2000)

[Publications] M.Kochi: "Magnetic Properties, Oxygen Content and Metal Valences in BaRE(Cu_<0.5> Fe_<0.5>)_2O_<5+δ> with RE=Lu, Yb, Y, Eu, Nd and Pr"Physica C. (In press). (2000)

[Publications] H.Yamauchi: "Water-containing Phases Derived from "02(n-1)n" Superconductors. I: Novel 02(n-1)n Homologous Series in the Ba-Ca-Cu-O System and the Derivative Series"Physica C. (In press). (2000)

[Publications] H.Yamauchi: "Water-containing Phases Derived from "02(n-1)n" Superconductors. II: Derivative of the Sr_2Ca_2Cu_3O_<8+δ>(0^<(Sr)>223) Phase"Physica C. (In press). (2000)

[Publications] H.Suematsu: "A Possible Cause of Peak Effect in Y-Ba-Cu-O Melt-Grown Bulks: Modulation in Oxygen Distribution"Physica C. (In press). (2000)

[Publications] M.Karppinen: "Oxygen Non-stoichiometry and Hole Distribution in Multi-layered Copper Oxides: Understanding of the Magnetic Irreversibility Characteristics"Physica C. (In press). (2000)

[Publications] T.Akao: "Irreversibility-field Enhancement by Optimizing Hole Density Distribution in the Hg-1212 Superconductor"Physica C. (In press). (2000)

[Publications] Y.Takahama: "Dependence of Peak Effect on Particle Size Distribution in Superconducting SmBa_2Cu_3O_<7-δ> Powder Samples"Physica C. (In press). (2000)

[Publications] T.Nakane: "Effects of Sr Substitution on the Magnetic-field Irreversibility in Superconductive Cu(Ba_<1-y>Sr_y)_2YbCu_2O_<6+z>;"Physica C. (In press). (2000)

[Publications] H.Yamauchi: "Stabilization and Oxidation-State Control of Novel Superconductive and Related Multi-Layered Copper Oxides"Superconductor Science and Technology. (In press). (2000)

[Publications] H.Suematsu: "Microstructural Cause of the Peak Effect in Superconducting Y-Ba-Cu-O Melt-Grown Bulks"J. Low Temp. Phys.. 117. 843-847 (1999)

[Publications] H.Yamauchi: "Carrier Distribution for Tailoring Superconducting Properties of Layered Cuprates; Journal of Low Temperature Physic"J.Low Temp.Phys.. 117. 813-822 (1999)

[Publications] M.Karppinen: "Superconducting Cuprates with Charge Reservoir Consisting of either Peroxide-Type Oxygen or H_2O"J. Low Temp. Phys.. 117. 843-847 (1999)

[Publications] K.Peitola: "Oxygen Stoichiometry in BaRE(Cu_<0.5>Fe_<0.5>)_2O_<5+δ> Compounds with Perovskite or Double Perovskite Structure"J. Low Temp. Phys.. 117. 861-865 (1998)

[Publications] T.Akao: "Peak Effect Caused by Compositional Modulation in Superconducting (Hg,Pb)(Ba,Sr)-1223 Single Crystal"J. Low Temp. Phys.. 117. 927-931 (1999)

[Publications] M.Karppinen: "Control of the Charge Inhomogeneity and High-T_c Superconducting Properties in Homologous Series of Multi-Layered Copper Oxides"Materials Science & Engineering Reports. 26. 59-96 (1999)

[Publications] H.Yamauchi: "The Peak Effect in High T_c Superconductors"Proceedings of 2^<nd> International Symposium on Electronic Component Material. 81-86 (1999)

山内尚雄東京工業大学, 応用セラミックス研究所, 教授 (50271581)