Elastic anomalies in a spin-crossover system: ferropericlase at lower mantle conditions.

摘要: The discovery of a pressure induced iron-related spin crossover in Mgð1-xÞFexO ferropericlase (Fp) and Mg-silicate perovskite, the major phases Earth’s lower mantle, has raised new questions about mantle properties which are central importance to seismology. Despite extensive experimental work on anomalous elasticity Fp throughout crossover, inconsistencies reported literature still unexplained. Here we introduce formulation for thermoelasticity systems, apply it by combining with predictive first principles density-functional theory on-site repulsion parameter U calculations, contrast results available data samples various iron concentrations. We explain why shear modulus should not soften along as observed some experiments, predict its velocities at conditions, show constraining elastic minerals without extrapolations analyses thermochemical state this region.