ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Bi4Ti3O12 nanoparticles were synthesized by chemical coprecipitation and crystallized in the perovskite structure after calcining at 520 °C. The dielectric properties were measured in bulk nanocrystalline compacts with different grain sizes. It was found that there were three peaks in the curves of the dielectric response as a function of temperature. The first peak shifts to higher temperature with decreasing grain size, which is considered to originate from the polarization of the ions in the conductive (Bi2O2)2+ layers across the potential barrier of the weak conductive perovskitelike layers. The second peak, contributed by the polarization of the defect dipoles on the grain surfaces, especially Bii〈sup ARRANGE="STAGGER"〉.–Vo″ dipoles, decreases gradually in intensity and finally disappears with increasing grain size. The last one, corresponding to a ferroelectric phase transition temperature, increases at first with decreasing grain size from 56 to 25 nm, then decreases with further decreasing grain size, and the mechanism is correlated with a competing effect of the released internal stresses and the clamped domain walls due to the diffusion of oxygen vacancies.© 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.367287
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