偏硼酸钡低温相晶体在高压下的电学性质与相变

 在金刚石压砧装置上，采用电容和电阻测量方法研究了偏硼酸钡低温相晶体（β-BaB₂O₄）在室温下和16 GPa内的电容、电阻与压力的关系。实验结果表明，它的电容在2.1、4.6、6.4、8、9.5、10.7 GPa左右都有一个突变。这说明β-BaB₂O₄内部的结构状态在这些压力下都发生了变化，可能发生了相变。还发现β-BaB₂O₄样品在较高压力下已发生了非晶化转变，而且是不可逆的，在卸压后被保留下来。这个非晶化转变的压力大约在11~12 GPa。

Electrical Properties and Phase Transitions in β-BaB2O4 at High Pressure

The capacitance, resistance-pressure relationships for the low temperature phase of barium metaborate (β-BaB₂O₄) have been studied at room temperature at pressure up to 16 GPa in a diamond anvil cell using capacitance and resistance measurements. Experimental results indicate that anomalous changes in capacitance with pressure occurring near 2.1, 4.6, 6.4, 8, 9.5 and 10.7 GPa. This shows the changes of structure or state in the interior of β-BaB₂O₄ at these pressures i.e., that β-BaB₂O₄ may undergoes phase transition. In the present work, it is known from X-ray diffraction analysis on the β-BaB₂O₄ sample after releasing pressure from 12 GPa that the sample has become amorphous. This shows that the β-BaB₂O₄ sample has already become amorphous state at higher pressure, and kept it after releasing. The amorphous transition pressure is about 11～12 GPa.