6533b862fe1ef96bd12c6f23

RESEARCH PRODUCT

High-pressure x-ray diffraction study of SrMoO4 and pressure-induced structural changes

Chaoyang TuRavhi S. KumarDaniel ErrandoneaXinghua Ma

subject

Condensed Matter - Materials SciencePhase transitionChemistrySpace groupMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesCrystal structureCondensed Matter PhysicsLandau theoryElectronic Optical and Magnetic MaterialsInorganic ChemistryTetragonal crystal systemCrystallographyPhase (matter)X-ray crystallographyMaterials ChemistryCeramics and CompositesPhysical and Theoretical ChemistryMonoclinic crystal system

description

SrMoO4 was studied under compression up to 25 GPa by angle-dispersive x-ray diffraction. A phase transition was observed from the scheelite-structured ambient phase to a monoclinic fergusonite phase at 12.2(9) GPa with cell parameters a = 5.265(9) A, b = 11.191(9) A, c = 5.195 (5) A, and beta = 90.9, Z = 4 at 13.1 GPa. There is no significant volume collapse at the phase transition. No additional phase transitions were observed and on release of pressure the initial phase is recovered, implying that the observed structural modifications are reversible. The reported transition appeared to be a ferroelastic second-order transformation producing a structure that is a monoclinic distortion of the low-pressure phase and was previously observed in compounds isostructural to SrMoO4. A possible mechanism for the transition is proposed and its character is discussed in terms of the present data and the Landau theory. Finally, the EOS is reported and the anisotropic compressibility of the studied crystal is discussed in terms of the compression of the Sr-O and Mo-O bonds.

https://dx.doi.org/10.48550/arxiv.0708.0028