High-pressure study of substrate material ScAlMgO4

TL;DR

This study investigates the structural behavior of the substrate material ScAlMgO4 under high pressure, revealing phase stability, transformation, and elastic properties up to 40 GPa, with implications for its use with ZnO.

Contribution

It provides the first detailed high-pressure structural analysis of ScAlMgO4, including phase transition points and elastic property measurements.

Findings

Stable up to 24 GPa

Reversible phase transformation at 28 GPa

Bulk modulus of 143 GPa with anisotropic compressibility

Abstract

We report on the structural properties of ScAlMgO4 studied under quasi-hydrostatic pressure using synchrotron high-pressure x-ray diffraction up to 40 GPa. We also report on single-crystal studies of ScAlMgO4 performed at 300 K and 100 K. We found that the low-pressure phase remains stable up to 24 GPa. At 28 GPa, we detected a reversible phase transformation. The high-pressure phase is assigned to a monoclinic distortion of the low-pressure phase. No additional phase transition is observed up to 40 GPa. In addition, the equation of state, compressibility tensor, and thermal expansion coefficients of ScAlMgO4 are determined. The bulk modulus of ScAlMgO4 is found to be 143(8) GPa, with a strong compressibility anisotropy. For the trigonal low-pressure phase, the compressibility along the c-axis is twice than perpendicular one. A perfect lattice match with ZnO is retained under pressure in the pressure range of stability of wurtzite ZnO.