Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7992795 | Journal of Alloys and Compounds | 2018 | 8 Pages |
Abstract
Pure, La-doped, and (La,Co)-codoped BiFeO3 ceramic samples were prepared by solid-state reaction. By means of dielectric permittivity, electric modulus spectroscopy, and impedance analysis, the dielectric properties of the samples were systematically investigated in the temperature range of 140-330â¯K and frequency range of 20-107â¯Hz. Three, two, and one dielectric relaxations were found in pure, La-doped, and (La,Co)-codoped samples, respectively, in the investigated temperature window. Post-sintering annealing studies reveal that both p- and n-types carriers coexist in the samples with the p-type carriers (holes) being the major carriers acting as relaxing species. The dielectric properties are determined by the competition between the n-type carriers (electrons) and the holes. La-doping and (La,Co) dual doping enhance the role played by the holes. Impedance analysis shows that the low-temperature (high-frequency) relaxation is a polaronic relaxation resulting from the hoping motion of holes inside grains. The middle-temperature (frequency) and high-temperature (low-frequency) relaxations are Maxwell-Wagner relaxations caused by the hoping motion of holes blocked by grain boundaries and sample-electrode contacts, respectively. These results underscore the role of sample preparing conditions in the dielectric properties of BiFeO3 and suggest that optimizing the preparing procedures would be a promising strategy to achieve superior properties of BiFeO3.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Q.Q. Wang, C.C. Wang, N. Zhang, H. Wang, Y.D. Li, Q.J. Li, S.G. Huang, Y. Yu, Y.M. Guo, Z.Q. Lin,