层状钙钛矿结构锰氧化物Ca_3Mn_2O_7的压致结构相变

PRESSURE-INDUCED PHASE TRANSITIONS OF LAYERED PEROVSKITE-LIKE MANGANATES Ca_3Mn_2O_7

采用金刚石压砧高压装置 (DAC) ,对层状钙钛矿结构锰氧化物Ca3Mn2 O7的粉末样品进行了高压能散X射线衍射实验。实验结果表明 ,在 0～ 35GPa压力范围内 ,Ca3Mn2 O7晶体结构发生了两次相变。在 1 3GPa左右 ,由原来的四方相转变为正交相 ;在 9 5GPa左右 ,又由正交相向新的四方相转变。

In suit energy dispersive X ray diffraction measurements on layered perovskite like manganates Ca 3Mn 2O 7 under pressure up to 35GPa were performed by using diamond anvil cell with synchrotron radiation.The results show that two phase transitions occured in layered perovskite like manganates Ca 3Mn 2O 7 under pressures in the range of 0～35GPa.The crystal structure changes from tetragonal to orthorhombic at about 1.3GPa,and then from orthorhombic to tetragonal at about 9.5GPa,respectively.