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Advances in Condensed Matter Physics
Volume 2012 (2012), Article ID 913168, 7 pages
http://dx.doi.org/10.1155/2012/913168
Research Article

Origin of the Giant Negative Thermal Expansion in

1Department of Physics, University of Science and Technology of China, Anhui, Hefei 230026, China
2Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Anhui, Hefei 230026, China

Received 16 June 2012; Accepted 11 September 2012

Academic Editor: Koshi Takenaka

Copyright © 2012 B. Y. Qu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The giant negative thermal expansion in the Ge-doped antiperovskite Mn3CuN compound is theoretically studied by using the first principles calculations. We propose that such a negative thermal expansion property is essentially attributed to the magnetic phase transition, rather than to the lattice vibration of the Ge-doped compound. Furthermore, we found that the doped Ge atoms in the compound significantly enhance the antiferromagnetic couplings between the nearest neighboring Mn ions, which effectively stabilizes the magnetic ground states. In addition, the nature of the temperature-dependent changes in the volume of the Ge-doped compound was revealed.