Relaxation rate of conserved and nonconserved order parameters in replacive transitions.
Relaxation rate of conserved and nonconserved order parameters in replacive transitions.
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替代跃迁中保守和非保守有序参数的弛豫率。
DOI：
10.1103/physrevb.50.12362
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Mártin
中科院分区：
文献类型：
--
作者：
Mártin
我们应用动力学布拉格-威廉姆斯模型，最近推出，有序相的相干沉淀。我们证明了长程序参量（非守恒）和浓度（守恒序参量）的弛豫速率不仅与通常假设的自由能耦合，而且与线性算子中的非对角项耦合，线性算子将两个序参量的弛豫速率与驱动力联系起来，即，自由能泛函关于序参数的偏导数。此外，我们表明，松弛的非保守序参量可能会发生两条路线，一个均匀的（现场松弛）和非均匀的（迁移的域边界）。所有这些效应都被现有的理论所忽略。
We apply the kinetic Bragg-Williams model, introduced recently, to coherent precipitation of ordered phases. We show that the relaxation rate of the long-range order parameter (nonconserved) and of the concentration (conserved order parameter) are coupled not only by the free energy as usually assumed, but also by nondiagonal terms in the linear operator that connects the relaxation rate of both order parameters to the driving forces, i.e., the partial derivatives of the free-energy functional with respect to the order parameters. Moreover, we show that the relaxation of the nonconserved order parameter may occur by two routes, a homogeneous one (on site relaxation) and a heterogeneous one (migration of domain boundary). All such effects are ignored by existing theories.