Chinese Acad Sci, Ctr Condensed Matter Phys, Inst Phys, Lab Extreme Condit Phys, Beijing 100080, Peoples R China
; Chinese Acad Sci, Beijing High Pressure Res Ctr, Beijing 100080, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca3Mn2O7 is un table under pressure due to the easy compression of NaCl-type blocks. The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0 similar to 35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.