Temperature dependent near infrared ultraviolet range dielectric functions of nanocrystalline (Na0.5Bi0.5)(1-x)Ce-x(Ti0.99Fe0.01)O-3 films
Temperature dependent near infrared ultraviolet range dielectric functions of nanocrystalline (Na0.5Bi0.5)(1-x)Ce-x(Ti0.99Fe0.01)O-3 films
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纳米晶 (Na0.5Bi0.5)(1-x)Ce-x(Ti0.99Fe0.01)O-3 薄膜的温度依赖性近红外紫外范围介电函数
DOI：
10.1063/1.4863417
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发表时间：
2014
影响因子：
4
通讯作者：
Chu J. H.
中科院分区：
文献类型：
--
作者：
Zhang S.;Zhang J. Z.;Han M. J.;Li Y. W.;Hu Z. G.;Chu J. H.
用椭圆偏振光谱法研究了Ce掺杂的（Na{sub 0.5}Bi{sub 0.5}）（Ti{sub 0.99}Fe{sub 0.01}）O{sub 3}纳米晶薄膜在−70 ~ 500 °C的光学性质和相变。在0.6-6.4 eV的光子能量范围内的温度依赖的介电函数可以由Tauc-Lorentz模型导出。结果表明，在200和340 °C附近，样品的介电函数（ε）出现突变。这种现象可以用偏振的出现和/或反转来解释。结果表明，铁电（菱面体）到顺电（四方体）相变与电子能带变化有关，这是通过该技术观察到的。
Optical properties and phase transition of Ce-modified (Na{sub 0.5}Bi{sub 0.5})(Ti{sub 0.99}Fe{sub 0.01})O{sub 3} nanocrystalline films have been investigated by spectroscopic ellipsometry from −70 to 500 °C. Temperature dependent dielectric functions in the photon energy range of 0.6–6.4 eV can be derived by the Tauc-Lorentz model. It was found that the features in dielectric function (ε) showed an abrupt variation near 200 and 340 °C, respectively. The phenomena can be explained by the appearance and/or reversal of polarization. It indicates that ferroelectric (rhombohedral) to paraelectric (tetragonal) phase transition is related to electronic band variation, which is observed by this technique.