Dielectric relaxation and electrical conductivity of random oriented BiFeO₃ thin films

Abstract

Complex impedance and electric modulus spectroscopies were used to investigate the dielectric relaxation and conductivity of random oriented BiFeO₃ thin films. Thermally activated charge transport models yielded activation energies of $E \sim 0.46$ eV, which is consistent with an electrical conduction dominated by oxygen vacancies. The non-Debye behavior of impedance and electric modulus relaxations were modeled by Cole-Cole functions. Results suggest a coexistence of components from both long-range and localized relaxation in the studied BiFeO₃ films dominated by grain boundaries. The dielectric relaxation induced by electric field does not follow the Arrhenius formalism.

Keywords:

• Bismuth ferrite
• thin films
• dielectric relaxation

Acknowledgements

The authors would like to thank the Brazilian agencies CNPq (Research Grant 304604/2015-1 and Project No. 400677/2014-8) and FAPESP (Project 2017/13769-1) for the financial support.