Dielectric and aging behavior of multiferroic YbMnO3 ceramics

Dielectric behavior and aging phenomenon of multiferroic YbMnO3 ceramics were investigated. In the temperature range from 250 to 450 K, a Debye dielectric relaxation with an activation energy of 0.43 eV was observed. The dielectric constant decreased and the peak positions slightly shifted to higher temperatures as the aging time increased. The XRD and XPS results suggested that the phase decomposition and/or the change of valence state of Mn ions were not the origin of the dielectric aging. The observed aging phenomenon could be explained as a result of the time-dependent formation of defect dipoles (formed by positively charged oxygen vacancies and negatively charged Mn defects) and their re-orientations.