Tunable negative thermal expansion and structural evolution in antiperovskite Mn3Ga1-xGexN (0
Tunable negative thermal expansion and structural evolution in antiperovskite Mn3Ga1-xGexN (0
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反钙钛矿 Mn3Ga1-xGexN 中可调节的负热膨胀和结构演化（0
DOI：
10.1111/jace.15099
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发表时间：
2017
影响因子：
3.9
通讯作者：
Wang Cong
中科院分区：
文献类型：
--
作者：
Lu Huiqing;Sun Ying;Deng Sihao;Shi Kewen;Wang Lei;Zhao Wenjun;Han Huimin;Deng Shenghua;Wang Cong
系统研究了反钙钛矿化合物Mn 3Ga 1 −xGexN（0 ≤x≤ 1.0）的负热膨胀（NTE）和结构演化。X射线衍射（XRD）结果表明，随着Ge含量的增加，Mn 3Ga 1 − xGexN的晶体结构由立方（C）向四方（T4）转变，Mn 3Ga 1 −xGexN的负热膨胀系数从x =0（工作温度范围T= 20 K）tox= 0.4（T= 60 K）开始变宽并向高温移动，然后从x = 0.5开始变为正热膨胀系数。通常，Mn3Ga0.5Ge0.5N在300至450 K之间表现出低的热膨胀行为（Δ T= 150 K），热膨胀系数α估计为2 × 10− 6 K −1。此外，通过变温XRD测试，揭示了NTE的来源。在低温下观察到立方I-立方II相共存（x= 0.2）和立方I-四方晶系共存（x= 0.5，0.6）。这种可调谐NTE在精密器件的实际应用中具有很高的价值。
The negative thermal expansion (NTE) and structural evolution of antiperovskite compounds Mn3Ga1−xGexN (0 ≤x≤ 1.0) were systematically investigated. Our results indicate the crystal structure of Mn3Ga1−xGexN changes from cubic (C) to tetragonal (T4) with increasing Ge content by X‐ray diffraction (XRD).The negative thermal expansion fromx =0 (operation‐temperature range ▵T= 20 K) tox= 0.4 (▵T= 60 K) becomes broad and shifts to higher temperature, and then it became positive fromx= 0.5 in Mn3Ga1−xGexN. Typically, Mn3Ga0.5Ge0.5N shows low thermal expansion behavior between 300 and 450 K (∆T= 150 K), and thermal expansion coefficient α is estimated to be 2 × 10−6K−1. Furthermore, variable temperature XRD was measured to reveal the origin of NTE. The cubic I ‐ cubic II phases coexistence (x= 0.2) and cubic I ‐ tetragonal coexistence (x= 0.5, 0.6) was observed at low temperature. The tunable NTE is highly valuable for practical applications in precision devices.