High Pressure X-ray Diffraction Study of MgMn2O4 Tetragonal Spinel

TL;DR

This study investigates the structural phase transition of MgMn2O4 spinel under high pressure using X-ray diffraction, revealing how cation distribution affects transition pressure and material properties.

Contribution

It provides new insights into how inversion degree influences phase transition pressures and structural properties of MgMn2O4 spinel under high pressure.

Findings

Transition to orthorhombic structure at high pressure

Inversion degree affects transition pressure

Differences in volume contraction and density trends

Abstract

The phase stability of the MgMn2O4 spinel has been studied by means of high-pressure X-ray diffraction for pressures up to 30 GPa. Two samples with different inversion degrees have been considered. Both spinels undergo a phase transition towards an orthorhombic structure (CaMn2O4-type). For the more inverted sample the transition pressure is at least 1 GPa lower with respect to that of the less inverted spinel. Also the volume contraction, relative compressibility and density trends are different for the two samples. These variations have been explained according to differences in the cation distribution. and electronic properties of the samples.