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

TL;DR

This study investigates the structural stability and behavior of the non-oxide perovskite superconductor MgCNi$_{3}$ under high pressure up to 32 GPa, revealing consistent cubic symmetry and potential local distortions.

Contribution

First detailed high-pressure structural analysis of MgCNi$_{3}$ using synchrotron x-rays, confirming cubic symmetry and identifying possible local distortions at high pressures.

Findings

Structural remains cubic up to 32 GPa.

Bulk modulus B0 = 156.9 GPa, B0' = 9.8.

Anomalous shifts in (111) and (200) lines above 9 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.