Abstract
BiFeO3 nanoparticles (<200 nm) were synthesized using the Pechini method and submitted to structural, microstructural, magnetic and electrical investigations. Two different structural symmetries were proposed to describe the BiFeO3 structure and the observed electrical properties, rhombohedral (R3c space group) and orthorhombic (Pbmn). Electric conductivity results obtained as a function of temperature, show two completely reversible changes in the baseline (310 °C and 385 °C), indicating two magnetic corresponding transitions associated with the orthorhombic and rhombohedral symmetries. These transitions were linked to predicted insulating-metal transition when magnetic arrangement changes from antiferromagnetic to a nonmagnetic ordering.
Acknowledgements
The authors would like to thank the Brazilian agencies CNPq (proc. 309830/2017-6, 446565/2014-8, and 429687/2016-8), Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná (Pesquisa Básica e Aplicada 09/2016) and CAPES (Procad 88881.068509/2014-01) for financial support.