Summary of Research Project Results under JSPS FY2003
"Research for the Future Program"



1.Research Institution The University of Tokyo
2.Research Area Integrated Fields
3.Research Field Behavior of Substances and Organisms under High Magnetic Field
4.Term of Project FY 1999 - FY 2003
5.Project Number 99I00803
6.Title of Project Novel Effects in Melt Growth, Sintering and Crystallization under Strong Magnetic Field

7.Project Leader
Name Institution,Department Title of Position
Kohji, Kishio The University of Tokyo , Graduate School of Engineering Professor

8.Core Members

Names Institution,Department Title of Position
Tomoyuki ,Kakeshita Osaka University , Graduate School of Engineering Professor
Hideyuki,Yasuda Osaka University, Graduate School of Engineering Associate Professor
Isao, Tanaka University of Yamanashi ,Graduate School of Medical and Engineering Science Department of Research Professor

9.Summary of Research Results

We have investigated behaviors of melt growth, sintering and crystallization under strong magnetic fields for various functional materials such as metals, alloys, high-Tc cuprates, thermoelectric oxides and optical oxides in order to show effectiveness of strong magnetic fields environment as a production process of functional materials. On melt growth of oxides, we have constructed crystal growth equipments using floating zone method with two different heat sources, YAG laser and xenon lamp, and have prepared high-Tc bismuth cuprates using YAG laser and optical calcium-aluminum oxides using xenon lamps. By applying of magnetic fields, homogeneously dispersed oxygen bubbles in grown crystal were observed for calcium aluminum oxides, which is understood in terms that each oxygen bubble was magnetized and acts repulsively. On the other hand, obvious effects were not observed for bismuth high-Tc cuprates. For thermoelectric oxides, Highly c-axis oriented polycrystals of Ca-Co-O system were successfully prepared by magnetic fields of 3 tesla and the highest figure of merit in Ca-Co-O polycrystals was achieved. On monotectic In-Al alloy, In-solidification with rod-type in Al matrix was observed due to reduction of fluidity of melt by magnetic field. Moreover, using quenched sample of Bi-Mn alloy, magnetic orientation of ferromagnetic Bi-Mn phase was induced by crystallization of post-annealing under magnetic field. Using this process, we have successfully prepared locally ferromagnetized region using local annealing of focused laser beam in magnetic field. On ferromagnetic shape-memory alloy, magnetostriction as large as tefenol D was accomplished for Fe-Pd, Fe3Pt and Ni2MnGa and this phenomenon was quantitatively understood in terms that magnetic energy due to magnetic anisotropy was larger than kinetic energy for rearrangement of twin structures.

10.Key Words
(1)strong magnetic field   (2)melt growth   (3)sintering
(4)crystallization   (5)functional materials   (6)superconductors
(7)thermoelectric materials   (8)shape-memory alloy   (9)magnetic alignment

 

 


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