Origin of low-frequency dielectric permittivity in BiFeO3 multiferroic ceramics
- Resource Type
- Conference
- Authors
- Tu, C.-S.; Wang, T.-H.; Schmidt, V. H.; Chien, R. R.
- Source
- 2011 International Symposium on Applications of Ferroelectrics (ISAF/PFM) and 2011 International Symposium on Piezoresponse Force Microscopy and Nanoscale Phenomena in Polar Materials Applications of Ferroelectrics (ISAF/PFM), 2011 International Symposium on and 2011 International Symposium on Piezoresponse Force Microscopy and Nanoscale Phenomena in Polar Materials. :1-4 Jul, 2011
- Subject
- Components, Circuits, Devices and Systems
Engineered Materials, Dielectrics and Plasmas
Fields, Waves and Electromagnetics
X-ray scattering
Ceramics
BiFeO3
dielectric permittivity
barrier model
magneto-electric coupling
- Language
- ISSN
- 1099-4734
2375-0448
A one-dimensional conductivity barrier model is introduced to describe the dielectric response and conductivity of BiFeO 3 (BFO) and (Bi 0.95 Nd 0.05 )FeO 3 (BFO-5%Nd) ceramics as functions of temperature and frequency. Good qualitative fits of conductivity and dielectric permittivity in the intermediate-temperature region (500–800 K) are obtained with intrinsic barriers of B=8700 K (for BFO) and B=8400 K (for BFO-5%Nd), and extrinsic barriers of Δ=2500 K (for BFO and BFO-5%Nd). The phase-shifted conductivity is responsible for a step-like dielectric relaxation in the region of 500–800 K. The experimental conductivity departs from the conductivity-barrier-model fit below 650 K. This deviation is likely caused by the magneto-electric coupling near the antiferromagnetic-paramagnetic transition. This work suggests that the 5% mole Nd-substitution can stabilize the perovskite structure in BFO ceramic.