Ferroelectricity of multiferroic hexagonal TmMnO3 ceramics synthesized under high pressure

Dense hexagonal TmMnO₃ ceramics were synthesized by solid-state reaction technique combined with high-pressure treatment which significantly increased the density of ceramic samples. The crystal structure of the hexagonal TmMnO₃ oxide was refined by using Rietveld analysis based on powder x-ray diffraction experiment. We observed obvious dielectric peaks through dielectric measurement on the specimen subjected to postannealing in oxygen atmosphere. A ferroelectric-paraelectric transition around 348°C is identified. Polarization-electric field hysteresis (P-E ) loop measurement proved the ferroelectricity of the sample at room temperature.