Dr
Sandra Helen Skjaervoe
(NTNU Norwegian University of Science and Technology, Department of Materials Science and Engineering, NO-7491 Trondheim, Norway)
The structural coherence across the ferroelectric transition in improper ferroelectric YMnO3 and other related multiferroic hexagonal manganites is not well understood. Here we reveal the evolution of the local structure in YMnO3 using neutron total scattering and first-principles calculations. We show that, at room temperature, the local and average structures are consistent with the established ferroelectric ground state structure. On heating from~ 800 K and up to above TC, both local and average structural analyses show striking anomalies consistent with increasing fluctuations of the order parameter angle. The fluctuations give an unusual local symmetry lowering into a continuum of structures which coincides well with reported temperatures for which the observable polarization vanishes, persisting into the high-symmetry non-polar phase.
Dr
Sandra Helen Skjaervoe
(NTNU Norwegian University of Science and Technology, Department of Materials Science and Engineering, NO-7491 Trondheim, Norway)
Mr
Quintin Noel Meier
(ETH, Materials Theory, Wolfgang Pauli Str. 27, CH-8093 Zürich, Switzerland)
Mikhail Feygenson
(Forschungszentrum Jülich, JCNS, D-52425 Jülich, Germany, Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA)
Prof.
Nicola Ann Spaldin
(ETH, Materials Theory, Wolfgang Pauli Str. 27, CH-8093 Zürich, Switzerland)
Prof.
Simon J. L. Billinge
(Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, NY 11973, USA, Columbia University, Department of Applied Physics and Applied Mathematics, New York, NY 10027, USA)
Dr
Emil S. Bozin
(Brookhaven National Laboratory, Condensed Matter Physics and Materials Science Department, Upton, NY 11973, USA)
Prof.
Sverre Magnus Selbach
(NTNU Norwegian University of Science and Technology, Department of Materials Science and Engineering, NO-7491 Trondheim, Norway)
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