|08-158||José de los Santos Guerra||Martínez-Camejo, Y.(Universidade Federal de Uberlândia); Peláiz-Barranco, A.(Universidad de La Habana); de los Santos Guerra, J.(Universidade Federal de Uberlândia); Santos, I.A.(Universidade Estadual de Maringá);|
The physical properties of the rare-earth modified BiFeO3 (BFO) multiferroic system have been investigated, considering the substitution of the bismuth ion placed in the A site of the perovskita structure. The influence of the rare-earth content on the structural, microstructural and dielectric properties were taken into account. The obtained results suggest that the smaller rare-earth doping ion (Gd) tend to occupy both the A- and B-sites of the perovskite structure, revealing thus its amphoteric character. Through the investigation of the dielectric properties, performed on cryogenic temperatures, it was also possible to identify a low temperature dielectric anomaly, which has been related to both the double- and super-exchanges interactions mechanisms, related to the magnetic component of the ferrite BFO samples. On the other hand, the ionic radius dependence of the activation energy has shown that the Gd ion strongly affected the defect mechanisms through oxygen vacancies, which confirm the amphoteric characteristics of the Gd ion.ACKNOWLEDGMENTS: The authors would like to thank to FAPEMIG, CNPq and CAPES Brazilian agencies for financial support.