| Autor: |
de la Flor, G., Mihailova, B. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 5/21/2020, Vol. 127 Issue 19, p1-11, 11p, 1 Diagram, 1 Chart, 13 Graphs |
| Abstrakt: |
In situ temperature-dependent Raman-scattering experiments under an external dc electric field E have been performed on (1 − x)Na 0.5 Bi 0.5 TiO 3 - x BaTiO 3 single crystals with x ranging from 0.013 to 0.074 in order to gain further insights into the atomistic mechanism of polar coupling in lead-free perovskite-type (ABO 3) ferroelectric solid solutions near the morphotropic phase boundary (MPB). The polarized Raman spectra collected between 770 and 100 K under an E applied along the pseudocubic [100] direction were analyzed in terms of hard-mode spectroscopy. The results reveal enhanced coupling between the polar displacements of the A-site Bi 3 + and B-site Ti 4 + cations for x = 0.048 ∼ x M P B when a moderate E [ 100 ] field is applied, a local-scale phenomenon that might be responsible for the known drift of the MPB under external stimuli. In addition, for all studied compounds, the characteristic temperatures T A − A ′ and T A − A ′ ′ , preceding the macroscopic T m and T d and related to mesoscopic-scale antiferroelectric and ferroelectric coupling processes within the A-site-cation subsystem in a zero field, merge into one even under a weak electric field, suggesting that the structural state between the paraelectric and ferroelectric zones in the x -T diagram is weak ferrielectric. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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