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Negative thermal expansion induced by intermetallic charge transfer
Masaki Azuma1, Kengo Oka2, Koichiro Nabetani1
1Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.
Science and Technology of Advanced Materials
|November 24, 2016
Summary
Negative thermal expansion (NTE) materials shrink when heated, offering industrial benefits. This study reviews NTE in specific perovskites, highlighting a colossal effect near room temperature controllable by substitution.
Area of Science:
- Materials Science
- Solid State Physics
- Chemistry
Background:
- Thermal expansion is critical for industrial applications, driving interest in materials with negative thermal expansion (NTE).
- NTE materials exhibit the unique property of shrinking upon heating and expanding upon cooling.
- Understanding the mechanisms behind NTE is key to developing advanced materials.
Approach:
- This work provides an overview of NTE phenomena.
- Focuses on intermetallic charge transfer as the driving mechanism for NTE.
- Examines NTE in A-site ordered double perovskites (LaCu3Fe4O12, LaCu3Fe4-xMnxO12) and substituted BiNiO3.
Key Points:
- Intermetallic charge transfer is identified as the mechanism inducing NTE in the studied perovskites.
- LaCu3Fe4O12 and LaCu3Fe4-xMnxO12 exhibit NTE due to this charge transfer mechanism.
- BiNiO3, particularly with Bi or Ni substitution, demonstrates significant NTE.
Conclusions:
- The substituted BiNiO3 compound shows a colossal linear thermal expansion coefficient greater than -70 × 10^-6 K^-1 near room temperature.
- The temperature range for this colossal NTE can be tuned through chemical substitution.
- These findings underscore the potential of NTE materials for technological applications requiring precise dimensional stability.
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