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DOE OSTI · 2419442

Pressure-induced charge-transfer and structural transition in hexagonal multiferroic HoMnO 3

Ottesen, Martin·Ehrenreich-Petersen, Emma·Kronbo, Camilla Hjort·Baudelet, François·Nataf, Lucie·Kantor, Innokenty·Jørgensen, Mads Ry Vogel·Bremholm, Martin
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Abstract

The structural properties of the hexagonal multiferroic ℎ-HoMnO 3 under high pressure have been explored using synchrotron x-ray diffraction and x-ray absorption spectroscopy in diamond anvil cells. The structure was found to undergo a pressure-induced phase transition at ~24 GPa to a rhombohedrally distorted superstructure, which is isostructural to the oxygen-loaded h-RMnO 3+δ (R = Y,Dy,Ho,Er; δ ≈ 0.28) phases found in the same systems. The driving force behind the phase transition is the highly compressible ab plane which facilitates a gradual charge disproportionation of Mn(III) with pressure. We speculate this stabilizes the spin-liquid phase due to ferromagnetic coupling between neighboring Mn(II)/Mn(IV) and Mn(III). In addition, we demonstrate that the structural behavior is highly susceptible to nonhydrostatic conditions and the choice of pressure medium should be carefully made.

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75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYFrustrated magnetismHigh-pressure studiesMaterials ScienceMultiferroicsPhase transitionsPhysicsPressure effectsRare-earth magnetic materialsX-ray absorption spectroscopyX-ray powder diffraction

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Ottesen, Martin, Ehrenreich-Petersen, Emma, Kronbo, Camilla Hjort, Baudelet, François, Nataf, Lucie, Kantor, Innokenty, Jørgensen, Mads Ry Vogel, Bremholm, Martin. 2023-04-25. Pressure-induced charge-transfer and structural transition in hexagonal multiferroic HoMnO 3. https://doi.org/10.1103/physrevb.107.134115

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