硼酸锂系列晶体的高压拉曼散射研究

本文进行了硼酸锂系列晶体的高压拉曼散射及其压致相变的研究。对于三硼酸锂（ＬｉＢ３Ｏ５），我们发现在５．０ＧＰａ有一可逆的晶态到晶态的相变，在２７．０ＧＰａ有一不可逆的晶态到非晶态的相变。二硼酸锂（Ｌｉ２Ｂ４Ｏ７）不可逆压致非晶相变发生在３２．０ＧＰａ附近。对于一硼酸锂，我们研究了０—５５．８ＧＰａ范围内的高压拉曼光谱，只在２．０ＧＰａ发现了一个晶态到晶态的相变，但未发现不可逆压致非晶化现象。在硼酸锂系列晶体中，不可逆压致非晶化的压力随Ｌｉ２Ｏ的含量的增加而升高。硼酸锂晶体中Ｌｉ２Ｏ的含量越高，压致非晶化越不容易发生，这与熔体急冷法制备硼酸锂玻璃的规律是一致的。

High Pressure Raman Scattering Study of Lithium Borate Crystals

In this paper, we report the study on the high pressure Raman spectra of lithium borate crystals and their pressure induced phase transitions. For lithium triborate, there is a reversible crystalline to crystalline transition at 5 0 GPa and an irreversible crystalline to amorphous state transition at 27 0 GPa. For lithium diborate, the irreversible pressure induced amorphization transition occurs at 32 0 GPa. We also studied the high pressure Raman spectra of lithium monoborate in the range of 0-55 8 GPa, crystalline to crystalline transition is found but, no irreversible pressure induced amorphization is observed. We conclude that for the series of lithium borate crystals, the pressure of the irreversible amorphization transition increases with the increase in the amount of Li 2O. The higher the content of Li 2O, the harder the pressure induced amorphization. This dependence is consistent with the preparation of amorphous lithium borate by the rapid cooling method.