Processing and properties of pure antiferromagnetic h-YMnO3

Yttrium manganite (YMnO3) is widely investigated multiferroic material with potential use in many technological applications. In this paper, we report on the preparation and characterization of multiferroic hexagonal YMnO3 ceramics obtained by chemical synthesis route. Precursor powders were prepared by the polymerizable complex method from citrate precursors. After calcination at 900 degrees C the powders contained mixture of Y-Mn-O phases which were further sintered at different temperatures. XRD analysis revealed that sintering at 1400 degrees C resulted in the formation of pure hexagonal YMnO3. Density of the obtained ceramics was 96 %TD. The ceramic samples proved to have multiferroic properties - they are antiferromagnetic below 42 K with linear dependence of magnetization as a function of applied magnetic field. The ferroelectric measurements performed at room temperature showed remanent polarization of 0.21 mu C/cm(2) and the coercive field of 6.0 kV/cm for the YMnO3 sample sintered at 1400 degrees C. The magnetization curves measured at 2 and 5 K for the powder samples calcined at 900 degrees C and ceramic samples sintered at 1300 degrees C exhibited a hysteresis loop due to a small concentration of Mn3O4 in the samples.