High pressure X-ray diffraction study of CaMnO3 perovskite

Using a diamond anvil cell device and synchrotron radiation, the in-situ high-pressure structure of CaMnO3 has been investigated. In the pressure up to 36.5 GPa, no pressure-induced phase transition is observed. The pressure dependence on the lattice parameters of CaMnO3 is reported, and the relationship of the axial compression coefficients is βa > βc > βb. The isothermal bulk modulus K298 = 224 (25) GPa is also obtained by fitting the pressure-volume data using the Murnaghan equation of state.