The Haven ratio in glasses
The Haven ratio in glasses
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DOI：
10.1016/s0022-3093(99)00036-8
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发表时间：
1999-04
影响因子：
3.5
通讯作者：
J. O. Isard
中科院分区：
文献类型：
--
作者：
J. O. Isard
如果离子迁移的活化能有一定的分布，则空位机制会产生较低的避风港比。在任何给定地点，只有一小部分跳跃向量是有效的，导致有效配位数低。给出了基于渗流理论的简化处理，表明如果标准偏差在0.05 ~ 0.15 eV之间，则会出现0.2 ~ 0.5的值。与一些实验结果一致，期望有一个低的正温度系数。
Low values of Haven ratio are shown to arise by the vacancy mechanism if there is a distribution of activation energies for ion migration. Only a fraction of the jump vectors at any given site will be effective leading to low effective coordination numbers. A simplified treatment based on percolation theory is given which suggests that values in the range 0.2–0.5 will occur if the standard deviation is between 0.05 and 0.15 eV. A low positive temperature coefficient is expected in agreement with some experimental results.