2005 Fiscal Year Final Research Report Summary
Development of Magnetoresistive Halfmetals and Halfmetallic Composites for Spintronics
| Project/Area Number |
15206071
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
KARPPINEN Maarit Tokyo Institute of Technology, Materials and Stuctures Laboratory, Associate Professor, 応用セラミックス研究所, 助教授 (50334529)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI Yoshio Tokyo Institute of Technology, National Institute for Materials Science, Chief Researcher, 物質研究所, 主席研究員 (80354398)
MOTOHASHI Teruki Tokyo Institute of Technology, Materials and Structures Laboratory, Research Associate, 応用セラミックス研究所, 助手 (00323840)
YAMAUCHI Hisao Tokyo Institute of Technology, Materials and Structures Laboratory, Professor, 応用セラミックス研究所, 教授 (50271581)
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| Project Period (FY) |
2003 – 2005
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| Keywords | halfmetals / spintronics / double perovskite oxides / tunneling magnetoresistance / mixed valence state / Mossbauer spectroscopy / sol-gel method / composites |
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| Research Abstract |
Our three-year project was focused on halfmetallic (HM) oxide materials that are conducting ferromagnets with 100 % spin-polarized carriers (in an ideal case). Such materials form the bases for tunneling-type magnetoresistance (TMR) devices application of which is found in the presently emerging new technology called spintronics. Among the handful of HM materials discovered so far, B-site ordered double-perovskite (DP) oxides, A_2B'B''O_6, including the prototype Sr_2FeMoO_6 compound are the most promising candidates for room-temperature (RT) low-field (LF) application. The B-site ordered DPs were also in the central role in the present project, though related perovskite-derived systems were investigated as well. The goal of the project was to search for the limits of these materials to function as RT-LF-TMR materials by means of controlling their intrinsic and extrinsic material characteristics. The research included the following aspects:
(i) Tailoring of atomic-level intrinsic characteristics of Sr_2FeMoO_6 and related DP oxides
(ii) Control of the size of grains/magnetic domains by the choice of synthesis conditions
(iii) Design of composite structures to enhance the RT-LF TMR characteristics
(iv) Search for novel HM compound(s) among perovskite oxides
Our unique (new) material design and tailoring scheme itself, comprising atomic-to-macroscopic dimensional manipulation of various intrinsic and extrinsic material parameters, turned out to be highly successful. We positively believe that our approach will be found useful in future too to achieve a more organized and highly productive design scheme for a wide range of frontier materials.
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[Journal Article] Hole-doping into Co-12s2 copper oxides with s fluorite-structured layers between CuO_2 planes2006
Author(s)
H.Fjellvag, Y.Morita, T.Nagai, J.M.Lee, J.M.Chen, R.S.Liu, B.C.Hauback, V.P.S.Awana, Y.Matsui, H.Yamauchi, M.Karppinen
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Journal Title
Journal of Solid State Chemistry 179
Pages: 632-645
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Systematic induction of superconductivity in the Cu(Y_1-xCa_x)Ba_2Cu_2O_6+δ(δ【approximately equal】0.3) system by Ca substitution2005
Author(s)
V.P.S.Awana, M.A.Ansari, R.Nigam, A.Gupta, S.B.Samanta, R.B.Saxena, H.Kishan, V.Ganesan, A.V.Narlikar, M.Arai, M.Karppinen, H.Yamauchi, D.Buddhikot, S.K.Malik
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Journal Title
Superconductor Science and Technology 18
Pages: 716-720
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Systematic induction of superconductivity in the Cu(Y_<1-x>Ca_x)Ba_2Cu_2O<6+δ> (δ 【approximately equal】 0.3) system by Ca substitution2005
Author(s)
V.P.S.Awana, M.A.Ansari, R.Nigam, A.Gupta, S.B.Samanta, R.B.Saxena, H.Kishan, V.Ganesan, A.V.Narlikar, M.Arai, M.Karppinen, H.Yamauchi, D.Buddhikot, S.K.Malik
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Journal Title
Superconductor Science and Technology 18
Pages: 716-720
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Superconductivity with transition temperature up to 80 K for TbSr_2Cu_2.7Mo_0.3O_7+δ2003
Author(s)
V.P.S.Awana, A.Gupta, H.Kishan, E.Takayama-Muromachi, T.Watanabe, M.Karppinen, H.Yamauchi, S.K.Malik, W.B.Yelon, V.Ganesan, A.V.Narlikar
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Journal Title
Solid State Communications 129
Pages: 117-121
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Superconductivity with transition temperature up to 80 K for TbSr_2Cu_<2.7>Mo_<0.3>O_<7+δ>2003
Author(s)
V.P.S.Awana, A.Gupta, H.Kishan, E.Takayama-Muromachi, T.Watanabe, M.Karppinen, H.Yamauchi, S.K.Malik, W.B.Yelon, V.Ganesan, A.V.Narlikar
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Journal Title
Solid State Communications 129
Pages: 117-121
Description
「研究成果報告書概要(欧文)」より
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