LOW TEMPERATURES DIELECTRIC ANOMALY IN BiFeO3-BASED MULTIFERROIC CERAMICS

摘要

The dielectric properties have been investigated at cryogenic temperatures in single-phase multiferroic ceramics based on BiFeO3 system. The samples were obtained from the solid-state reaction sintering method, considering the inclusion of rare-earth elements according to the chemical formula Bi_(1-x)Gd_xFeO3 (x=0.10). Results revealed a dielectric anomaly, with a strong frequency dispersion of the dielectric permittivity, for temperatures around 200 K. Such anomalies could be one more evidence of the existence of an intermediate phase transition from different electric ordering, as consequence of a change in A-cation displacement. The dielectric relaxation mechanisms have also been investigated in details. The obtained results were discussed wimin the framework of the current models reported in the literature for dielectric relaxation processes.