本文研究了具有四方结构的(Na(1-x)Kx)0.5Bi0.5TiO3体系中x=0.22,0.26和0.30陶瓷材料不同温度下的电滞回线,结合变温XRD和介电温谱分析,发现该体系四方结构的组成为反铁电体,但紧靠准同型相界的四方结构由于场诱导下引起的反铁电-铁电相变,表现出铁电体特性,材料在升温过程中由于反铁电宏畴向微畴的转变导致了介电峰的产生,且在介电温谱上表现出强烈的介电常数-频率依赖性,为弛豫铁电体特征。
In this paper, the hysteresis loops and XRD patterns at different temperatures as well as dielectric constant as a function of temperature for (Na(1-x)Kx)0.5Bi0.5TiO3( x = 0.22,0.26, 0.30) ceramic composites composites with tetragonal symmetry structure were investigated. It is found that the tetragonal structure are anti-ferroelectric, but the composite near to the morphotropic phase boundary (MPB) showed ferroelectric characteristic because the anti-ferroelectric to ferroelectric phase transition was induced under electric field. The intense dependence of dielectric constant to frequency shows these materials are relaxor ferroelectric, and the appearance of the dielectric peak at heating process is caused by the transition of anti-ferroelectric macro-domain to micro-domain.