We reported previously [T. Chatterji , Phys. Rev. B 78, 134105 (2008)] negative thermal expansion (NTE) in ReO3 in the limited temperature range from 2 to 220 K. Here we discovered NTE in ReO3 at higher-temperature region from 600 to 680 K. We determined the temperature variation in the lattice parameter and the unit cell volume of ReO3 by neutron diffraction. The temperature variation in the lattice parameter and the unit cell volume show two regions of NTE and two minima. We attribute the NTE of ReO3 to be the result of anharmonicity and anomalous softening of M-3 phonon mode.
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机译:我们以前曾报道过[T.查特吉物理学Rev. B 78,134105(2008)]在2至220 K的有限温度范围内,ReO3中的负热膨胀(NTE)。在这里,我们在600至680 K的高温区域发现ReO3中的NTE。中子衍射改变ReO3的晶格参数和晶胞体积。晶格参数和单位晶胞体积中的温度变化显示两个区域的NTE和两个最小值。我们将ReO3的NTE归因于M-3声子模式的失谐和异常软化。
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