Differences in nature of electrical conductions among Bi4Ti3O12-based ferroelectric polycrystalline ceramics
Abstract Bismuth titanate Bi4Ti3O12 (BiT), was one of the most promising lead-free high-temperature piezoelectric materials, due to high Curie temperature (675 °C) and large spontaneous polarization (50 µC/cm2); however, extensive studies had revealed that high leakage conductivity interferes with t...
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| Autores principales: | , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Nature Portfolio
2017
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/a3aa3fc8bfdd47a2bee4b12674f6b2ee |
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| Sumario: | Abstract Bismuth titanate Bi4Ti3O12 (BiT), was one of the most promising lead-free high-temperature piezoelectric materials, due to high Curie temperature (675 °C) and large spontaneous polarization (50 µC/cm2); however, extensive studies had revealed that high leakage conductivity interferes with the poling process, hindering its practical applications. In this paper, an electrically insulating property was achieved by a low level Nb donor substitution to suppress a high level of holes associated with high oxygen vacancy concentration. Bi4Ti2.97Nb0.03O12 ceramic showed significant enhancements of electrical resistivity by more than three order of magnitude and activity energy with value >1.2 eV, which are significant for piezoelectric applications of BiT-based materials. However, pure and A2O3-excess (A = Bi, La and Nd; 3 at %) BiT ceramics, were mixed hole and oxygen ion conductors. Schottky barriers were both formed at grain boundary region and the sample-electrode interface, because of the existence of semiconducting bulk. Interestingly, the electron conduction could be suppressed in N2, as a consequence, they became oxide ion conductors with conductivity of about 4 × 10−4 S cm−1 at 600 °C. |
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