2026-06-01T09:39:50Z https://icatplus.esrf.fr/oaipmh/request

oai:icatplus.esrf.fr:inv/2107750542 2025-05-13T06:02:07.813Z

4.2 EI 10.15151/ESRF-ES-2107750542 Pierre BOUVIER Pierre Bouvier 0000-0003-1882-6786 Pierre BOUVIER Pierre Bouvier 0000-0003-1882-6786 Sitaram RAMAKRISHNAN Sitaram Ramakrishnan 0000-0001-6065-4178 Sitaram RAMAKRISHNAN Sitaram Ramakrishnan 0000-0001-6065-4178 Bjorn WEHINGER Bjorn Wehinger 0000-0002-7089-595X Mael GUENNOU Mael Guennou 0000-0001-9349-3024 Mael GUENNOU Mael Guennou 0000-0001-9349-3024 Mohamad baker SHOKER Mohamad Baker Shoker 0000-0002-1842-4712 Mohamad baker SHOKER Mohamad Baker Shoker 0000-0002-1842-4712 Example Institute 2028 Data from large facility measurement 2025-05-09T06:00:00Z/2025-05-13T06:00:00Z 2025-05-13T06:00:00Z I CC-BY-4.0 The overarching aim of this project is to re-examine the long-debated issue of the pressure-induced inversion symmetry breaking in perovskite oxides. Although this phenomenon is now commonly accepted theoretically, experimental evidence has been elusive, to say the least. The most recent efforts including our own have failed to confirm its occurrence in the most natural candidate and classical ferroelectric perovskite PbTiO3. However, we have realised very recently that KNbO3 (KNO) makes a much better candidate: our first results by room temperature XRD and Raman spectroscopy at high pressures (HP) show that KNO undergoes a phase transition from cubic to tetragonal that is unlike all known perovskites and shows all characteristics expected for the long awaited HP ferroelectric transition. The purpose of this proposal is to extend the phase diagram to low temperatures and map for the first time this original phase boundary with pressure and temperature.