Evidence for a pressure-induced spin transition in olivine-type LiFePO${}_4$ triphylite

Abstract

We present a combination of first-principles and experimental results regarding the structural and magnetic properties of olivine-type LiFePO${}_4$ under pressure. Our investigations indicate that the starting $Pbnm$ phase of LiFePO${}_4$ persists up to 70 GPa. Further compression leads to an isostructural transition in the pressure range of ~70-75 GPa, inconsistent with a former theoretical study. Considering our first-principles prediction for a high-spin to low-spin transition of Fe${}^{2+}$ close to 72 GPa, we attribute the experimentally observed isostructural transition to a change on the spin state of Fe${}^{2+}$ in LiFePO${}_4$. Compared to relevant Fe-bearing minerals, LiFePO${}_4$ exhibits the largest onset pressure for a pressure-induced spin state transition.

arXiv commentManuscript: 9 pages, 8 figures, 1 table. Supplemental Material: 4 figures, 5 tables

References in corpus (5)

• First-principles prediction of redox potentials in transition-metal compounds with LDA+U
• Anomalous compressibility of ferropericlase throughout the iron spin crossover
• Spin-state crossover and hyperfine interactions of ferric iron in MgSiO${}_3$ perovskite
• Spin crossover in ferropericlase from first-principles molecular dynamics
• First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle

Cited by in corpus (1)

• Quantum Magnetism in Minerals