Charge Density Distributions in Bi4Ti3O12 and Bi3.25La0.75Ti3O12 in the Paraelectric Phase

다국어 초록 (Multilingual Abstract)

The electron charge density distributions of the bismuth layered ferroelectric materials Bi4Ti3O12
(BiT) and Bi3.25La0.75Ti3O12 (BLT) in the paraelectric phase are demonstrated by analyzing the
high-energy synchrotron-radiation powder-diffraction data on the basis of the maximum entropy
method (MEM)/Rietveld method. The crystal structures of BiT and BLT are quite similar, and no
significant difference is observed in the chemical bonding nature in the paraelectric phase. This result
differs from the experimental fact that, in the ferroelectric phase, electron orbital hybridization
between Bi and O in the perovskite layer is formed along the a-axis in BiT while the hybridization
between Bi/La and O is revealed not only along the a-axis but also along the b-axis in BLT. We
attribute the unchanged Curie temperatures for the Bi4−xLaxTi3O12 system to the same crystal
structures, including the chemical bonding nature, in the paraelectric phase.

다국어 초록 (Multilingual Abstract)

The electron charge density distributions of the bismuth layered ferroelectric materials Bi4Ti3O12
(BiT) and Bi3.25La0.75Ti3O12 (BLT) in the paraelectric phase are demonstrated by analyzing the
high-energy synchrotron-radiation powder-diffraction data on the basis of the maximum entropy
method (MEM)/Rietveld method. The crystal structures of BiT and BLT are quite similar, and no
significant difference is observed in the chemical bonding nature in the paraelectric phase. This result
differs from the experimental fact that, in the ferroelectric phase, electron orbital hybridization
between Bi and O in the perovskite layer is formed along the a-axis in BiT while the hybridization
between Bi/La and O is revealed not only along the a-axis but also along the b-axis in BLT. We
attribute the unchanged Curie temperatures for the Bi4−xLaxTi3O12 system to the same crystal
structures, including the chemical bonding nature, in the paraelectric phase.

참고문헌 (Reference)

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