Structural Behavior of Non-Oxide Perovskite Superconductor MgCNi$_{3}$ at Pressures up to 32 GPa

Abstract

We report the pressure dependence of the structural parameters of the non-oxide perovskite superconductor MgCNi$_{3}$ up to 32 GPa using a diamond anvil cell and synchrotron x-rays at room temperature. The structure of the compound remains in the Pm-3m cubic symmetry throughout the pressure range. The bulk modulus $B_{0}=156.9\pm0.2$GPa with $B_{0}^{\prime}=9.8$obtained by fitting the pressure-volume data is in good agreement with theoretical calculations reported earlier. An anomalous shift of the (111) and (200) lines observed above 9 GPa indicates a possible local short range distortion that is consistent with earlier studies.