Conductivity is a main issue in research on multiferroic perovskite oxides, which makes the characterization of their ferroelectric properties difficult, and for several compounds even to unambiguously state their ferroelectric nature. In this report, we use ferroelectric BiMnO3-PbTiO3 as a model system to study the relationships among synthesis, processing, and conductivity in ABO3 perovskite oxides with magnetically active cations in the B-site. Three single phase, dense ceramic materials processed by conventional sintering, hot pressing, or spark plasma sintering (SPS) of powders synthesized by either wet chemistry or mechanochemical activation were studied. Impedance spectroscopy analysis was carried out to obtain grain and grain boundary conductivities for the three materials, along with activation energies. Mechanosynthesis is shown not to modify the mechanism of bulk or boundary conductivity, but only the carrier concentration, while SPS processing results in a low temperature, additional conduction mechanism. © 2013 Copyright Taylor and Francis Group, LLC.

This research was funded by MICINN (Spain) through project MAT2011-23709. HA thanks MICINN for funding through the RyC Programme. Collaboration of ICMM with CEMES is framed within the COST Action MP0904 (European Science Foundation, COST Programme).

Peer Reviewed