Crystal structure of NiO under high pressure

Eto, Tetsujiro*; Endo, Shoichi*; Imai, Motoharu*; Katayama, Yoshinori; Kikegawa, Takumi*

The pressure effect on the lattice constant of NiO with the rhombohedral distorted B1 structure was studied up to 141 GPa by angle-dispersive x-ray diffraction using synchrotron radiation, an imaging plate, and a diamond anvil cell. The lattice constant and , expressed in the hexagonal lattice, decrease monotonously with increasing pressure. The axial rage decreases monotonously with increasing pressure, indicating the distortion in the rhombohedral [111] direction becomes larger as pressure increases. The signiifcant change of above 60 GPa, suggested by a recent theoretical calculation, was not observed.