铌酸锶钡Sr1-xBaxNb2O6(0.25<x<075)陶瓷固溶体是典型的钨青铜结构弛豫型铁电体,其介电行为与钙钛矿结构弛豫型铁电体的介电行为极为相似,即射频介电温谱呈现弥散的居里温区.通过对Sr1-xBaxNb2O6(x=0.4、0.5、06)在─170~+400℃的介电温谱进行详细测定;与其热释电测量结果进行对比,发现它们在低温区的介电响应存在一个不同于钙钛矿结构弛豫型铁电体的弛豫过程,高于居里温区的介电响应很好地符合居里-外斯定律.结合钨青铜结构铁电体存在无公度相的特征,初步探讨了钨青铜结构弛豫型铁电体中局域极化的产生、增大和凝聚特点.
The complex dielectric response of tungsten bronze Sr1-xBaxNb2O6 [SBN(1--x)/x, x=0.40, 0.50 and 0.60] relaxor ferroelectric ceramics was
carefully studied as a function of temperature between --180℃ and 450℃. Three distinct relaxation features were observed in all the compositions.
The thermal hysteresis of dielectric maximum was considered to be associated with “lock in” of the incommensurate phase. It was confirmed by investigation of
the Curie-Weisis behavior at a higher temperature range. These results were also discussed in terms of the polarization fluctuation of polar microregions briefly.
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