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利用同步辐射x射线衍射和DAC高压技术在室温下测量了钙钛矿CaTiO3在压力 0— 4 4 5 3GPa下的结构变化 .结果表明 ,随着压力的增加CaTiO3的三个晶轴都受到不同程度的压缩 ,a ,b的压缩率相近且相对比较大 ,c的压缩率最小 ,但没有证据表明有相变的发生 .在压力范围内CaTiO3的P V关系用Murnaghan状态方程表示 ,设定K′0 =4 ,得到V0 =0 2 2 4 5 (6 )nm3和K0 =2 2 2 (9)GPa .应用赝立方角γpc与压力的关系 ,初步判断静水压下CaTiO3的结构对称性应降低
The structure change of perovskite CaTiO3 under pressure of 0-4-4 5 3GPa was measured by using synchrotron radiation x-ray diffraction and DAC high pressure technique. The results show that the three crystal axes of CaTiO3 are affected by different pressures , The compression rates of a and b are similar and relatively large, and the compression rate of c is the smallest, but there is no evidence of the occurrence of phase transition.The PV relationship of CaTiO3 in the pressure range is expressed by the Murnaghan equation of state, and K’0 = 4, we get V0 = 0 2 2 4 5 (6) nm3 and K0 = 2 2 2 (9) GPa. The structural symmetry of CaTiO3 should be preliminarily determined by using the relationship between the pressure and the pseudo-cubic angle γpc