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Discovery of New Materials That Shrink upon Heating (Press Release)

Release Date
15 Jun, 2011
  • BL02B2 (Powder Diffraction)
  • BL39XU (Magnetic Materials)
- Threefold shrinkage compared with those of conventional materials and their effectiveness for positioning precision equipment

Tokyo Institute of Technology
Kyoto University
Japan Synchrotron Radiation Research Institute
Japan Atomic Energy Agency

A research group led by Masaki Azuma (formally an associate professor at the Institute for Chemical Research, Kyoto University; currently a professor at the Materials and Structures Laboratory, Tokyo Institute of Technology), Yuichi Shimakawa (a professor at the Institute for Chemical Research, Kyoto University), Masaichiro Mizumaki (an associate senior scientist of the Japan Synchrotron Radiation Research Institute (JASRI)), and Tetsu Watanuki (an associate senior scientist of Japan Atomic Energy Agency) has discovered oxide materials that undergo negative thermal expansion*1 at least threefold that of conventional materials near room temperature. The group also found that the temperature range at which negative thermal expansion is observed can be controlled by changing the amount of additive elements.

Materials with negative thermal expansion are used to compensate the thermal expansion of structural materials when precise positioning is required for optical communication devices and semiconductor manufacturing equipment. It is hoped that the fabrication of zero-expansion materials*2 having high workability and zero expansion and zero shrinkage with changes in temperature will be possible by dispersing a small amount of the new materials into resin.

This research was carried out by the above-mentioned researchers jointly with scientists of The University of Tokyo, Hiroshima University, the University of Edinburgh (UK), and Rutherford Appleton Laboratory (UK). The results of this study were published in the British scientific journal Nature Communications on 14 June 2011.

Publication:
"Colossal negative thermal expansion in BiNiO3 induced by intermetallic charge transfer"
Masaki Azuma, Wei-tin Chen, Hayato Seki, Michal Czapski, Smirnova Olga, Kengo Oka, Masaichiro Mizumaki, Tetsu Watanuki, Naoki Ishimatsu, Naomi Kawamura, Shintaro Ishiwata, Matthew G. Tucker, Yuichi Shimakawa and J. Paul Attfield
Nature Communications 2, 347 (2011), published online 14 June 2011

<<Glossary>>
*1　Negative thermal expansion
The volume and length of materials generally increase upon heating, which is referred to as positive thermal expansion. However, the volumes of some materials shrink upon heating. This property is called negative thermal expansion and is very important in the development of zero-expansion materials.

*2　Zero-expansion materials
Zero-expansion materials do not expand or shrink upon heating. They are indispensable for precise positioning, a fundamental requirement in many nanotechnologies. Zero-expansion materials are realized by combining materials with positive and negative thermal expansion.

<<Figures>>

Fig. 1 Crystal structures of BiNiO3 under low pressure and temperature (left) and high pressure and temperature (right)
Fig. 1 Crystal structures of BiNiO3 under low pressure and temperature (left)
and high pressure and temperature (right)

Fig. 2 Change in length of Bi0.95La0.05NiO3 with temperature measured using strain gauge
Fig. 2 Change in length of Bi0.95La0.05NiO3 with temperature measured using strain gauge

Negative thermal expansion occurs between 7 and 127 oC, under which the linear thermal expansion coefficient is -82×10-6/oC, at least threefold higher than that of conventional materials.


For more information, please contact:
　Prof. Masaki Azuma (Tokyo Institute of Technology)
　　E-mail：mail

　Prof. Yuichi Shimakawa (Kyoto University)
　　E-mail：mail

　Dr. Masaichiro Mizumaki (JASRI)
　　E-mail：mail

　Dr. Tetsu Watanuki (Japan Atomic Energy Agency)
　　E-mail：mail