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arXiv · 1801.02953

Evidence for a pressure-induced spin transition in olivine-type LiFePO$_{4}$ triphylite

Maribel Núñez Valdez·Ilias Efthimiopoulos·Michail Taran·Jan Müller·Elena Bykova·Monika Koch-Müller·Max Wilke
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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.

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Maribel Núñez Valdez, Ilias Efthimiopoulos, Michail Taran, Jan Müller, Elena Bykova, Monika Koch-Müller, Max Wilke. 2018-01-16. Evidence for a pressure-induced spin transition in olivine-type LiFePO$_{4}$ triphylite. https://doi.org/10.1103/physrevb.97.184405

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