Soft-phonon feature, site defects, and a frustrated phase transition inNi50Ti47Fe3: Experiments and first-principles calculations
Soft-phonon feature, site defects, and a frustrated phase transition inNi50Ti47Fe3: Experiments and first-principles calculations
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Ni50Ti47Fe3 中的软声子特征、位点缺陷和受挫相变：实验和第一性原理计算
DOI：
10.1103/physrevb.77.024201
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发表时间：
2008
影响因子：
3.7
通讯作者：
K. Littrell
中科院分区：
文献类型：
--
作者：
M. Manley;M. Manley;M. Asta;J. Lashley;C. Retford;W. Hults;R. Taylor;Dan Thoma;J. Smith;R. Hackenberg;K. Littrell
用非弹性中子散射方法，在NiTi和Fe替代Ti的声子态密度（DOS）中观察到与NiTi形状记忆相变有关的软声子特征。在这两种合金中，该特征随温度降低而软化，但在Fe取代的合金中软化发生在约较低温度，表明转变温度降低。电阻率和磁化率验证了降低的转变温度，但也表明，过渡开发的二阶类似的行为观察到的其他（与Fe取代Ni）。穆斯堡尔谱和中子衍射支持的第一性原理计算表明，在Ti取代合金中，Fe占据Ni位，而取代的Ni占据空的Ti位。Ti取代合金的当前结果之间的比较，和相关的实验数据的合金具有Fe取代Ni，表明不稳定温度是由占据Ni位的Fe原子的数量控制，而二阶的行为是由添加的Ni反位缺陷引起的。我们认为，后者的行为的结果从相互作用的缺陷，以挫败破坏应变的破坏网络。
A soft-phonon feature associated with the shape-memory transition in NiTi is observed in the phonon density of states (DOS) of thephase of both NiTi and(with Fe substituted for Ti) using inelastic neutron scattering. In both alloys, the feature softens with decreasing temperature, but the softening occurs aboutlower in the Fe-substituted alloy, indicating a decreased transition temperature. Electrical resistivity and magnetic susceptibility verify the decreased transition temperature but also show that the transition develops second-order-like behavior similar to that observed by others in(with Fe substituted for Ni). First-principles calculations supported by Mössbauer spectroscopy and neutron diffraction indicate a double-defect scenario, where Fe occupies Ni sites and the displaced Ni occupies the empty Ti sites in the Ti-substituted alloys. A comparison between the current results for Ti-substituted alloys, and related experimental data for alloys featuring Fe substitution for Ni, indicates that the instability temperature is controlled by the number of Fe atoms occupying the Ni sites, while the second-order-like behavior is caused by the addition of the Ni antisite defects. We argue that this latter behavior results from percolated networks of interacting defects acting to frustrate the symmetry-breaking strains.
影响因子：
8.6
作者：
Sarkar, S;Ren, XB;Otsuka, K
通讯作者：
Otsuka, K
影响因子：
6
作者：
Choi, MS;Fukuda, T;Kakeshita, T
通讯作者：
Kakeshita, T