Spin crossover in ferropericlase from first-principles molecular dynamics

Abstract

Ferropericlase, (Mg,Fe)O, is the second-most abundant mineral of the Earth's lower mantle. With increasing pressure, the Fe ions in the material begin to collapse from a magnetic to non-magnetic spin state. We present a finite-temperature first-principles phase diagram of this spin crossover, finding a broad pressure range with coexisting magnetic and non-magnetic ions due to favorable enthalpy of mixing of the two. Furthermore, we find the electrical conductivity of the mineral to reach semi-metallic values inside the Earth.

References in corpus (6)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
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• Anomalous compressibility of ferropericlase throughout the iron spin crossover
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• Pressure-induced spin-state transition of iron in magnesiowüstite (Fe,Mg)O
• Anomalous thermal properties and spin crossover of ferromagnesite (Mg,Fe)CO3
• Evidence for a pressure-induced spin transition in olivine-type LiFePO${}_4$ triphylite
• Structural transition and re-emergence of iron's total electron spin in (Mg,Fe)O at ultrahigh pressure
• Electrical and Thermal Conductivity of Earth's Iron-enriched Basal Magma Ocean
• Reduced radiative conductivity of high and low spin FeO6 octahedra in the Earth's lower mantle