BiFeO3 Ceramics: Processing, Electrical, and Electromechanical Properties.
Journal of the American Ceramic Society, Volume 97, Issue 7, pages 1993–2011, July 2014.
Tadej Rojac1,†,*, Andreja Bencan1,Barbara Malic1,†, Goknur Tutuncu2,†,Jacob L. Jones3,†, John E. , Dragan Damjanovic5,†
- Electronic Ceramics Department, Jozef Stefan Institute, Ljubljana, Slovenia.
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida.
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina.
- School of Materials Science and Engineering, University of New South Wales, NSW, Australia.
- Ceramics Laboratory, Swiss Federal Institute of Technology – EPFL, Lausanne, Switzerland.
Bismuth ferrite (BiFeO3), a perovskite material, rich in properties and with wide functionality, has had a marked impact on the field of multiferroics, as evidenced by the hundreds of articles published annually over the past 10 years. Studies from the very early stages and particularly those on polycrystalline BiFeO3 ceramics have been faced with difficulties in the preparation of the perovskite free of secondary phases. In this review, we begin by summarizing the major processing issues and clarifying the thermodynamic and kinetic origins of the formation and stabilization of the frequently observed secondary, nonperovskite phases, such as Bi25FeO39 and Bi2Fe4O9. The second part then focuses on the electrical and electromechanical properties of BiFeO3, including the electrical conductivity, dielectric permittivity, high-field polarization, and strain response, as well as the weak-field piezoelectric properties. We attempt to establish a link between these properties and address, in particular, the macroscopic response of the ceramics under an external field in terms of the dynamic interaction between the pinning centers (e.g., charged defects) and the ferroelectric/ferroelastic domain walls.
© 2014 The American Ceramic Society.
Rich in properties and wide in functionality, bismuth ferrite (BiFeO3) has unambiguously marked the field of multiferroics. This has been manifested by the hundreds of papers published annually over the past ten years, with the numbers still increasing. Studies from the very early stages, dating back to the 1960’s, have been faced with difficulties in the preparation of BiFeO3 free of non-perovskite, parasitic phases. In addition, it has been soon realized that the ferrite exhibits a high electrical conductivity, creating difficulties in applying high electric fields to the material. The inability to pole the BiFeO3 ceramics with sufficiently high electric fields acted as a barrier in the exploration of their basic piezoelectric behavior. In the review paper, the authors begin by summarizing the major processing issues, clarifying the thermodynamic and kinetic origins of the formation and stabilization of the persisting secondary phases, Bi25FeO39 and Bi2Fe4O9. This section is accompanied by general guidelines that should be considered when undertaking the conventional solid-state synthesis of BiFeO3 ceramics. The second part of the paper focuses on the electrical and electro-mechanical aspect of BiFeO3, including the high-field response and weak-field piezoelectricity. After the conductivity issue is critically revised, the authors analyze in detail the domain switching behavior through studies of polarization and strain hysteresis loops. A large electric-field induced strain is revealed, comparable to that of the most efficient and technologically important lead-based ferroelectric ceramics, such as Pb(Zr,Ti)O3 (PZT) and Pb(Mg,Nb)O3–PbTiO3 (PMN-PT). The current status of BiFeO3 is motivating and oriented towards the exploitation of the BiFeO3-based materials in practical piezoelectric applications, which is, however, yet to be addressed.
Parasitic phases within a matrix of BiFeO3 grains (courtesy of E. Khomyakova). Inset: No. of publications on BiFeO3 per year (source: WoS).