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用助熔剂法制备了准同型相界附近的弛豫铁电体基钛铌铟酸铅(Pb(In1/2Nb12)0.63Ti0.37O3,简称PINT)铁电单晶体,研究了四氧化三铅(Pb3O4)与二氟化铅(PbF2)助熔剂对钙钛矿结构相稳定性的不同作用。用四氧化三铅(Pb3O4)和三氧化二硼(B2O3)作为助熔剂获得尺寸达5mm的纯钙钛矿相结构PINT单晶体,利用显微分析方法、X射线衍射技术研究了单晶体的微观形貌和相结构,测量了〈100〉取向单晶体样品的介电温度谱。 相似文献
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First principles study on lattice vibration and electrical properties of layered perovskite Sr_2M_2O_7(M=Nb,Ta) 下载免费PDF全文
In this paper, we performed calculations to investigate the dielectric, piezoelectric properties, Born effective charge(BEC), and spontaneous polarization of Sr_2M_2O_7, the method used in our study was a well-known density functional theory based on first-principles. The optimized results were in good agreement with previous experiments and calculations,which indicates that our calculated method is reasonable. The research we have done suggested that greater piezoelectric components of Sr_2Nb_2O_7 were e_(31) and e_(33), and the contributions were derived from the A_1. By studying the Born effective charge, it could be seen that the valence of ions changed, and the O of Sr_2Nb_2O_7 were most obviously that caused by the covalent character of ions and the hybridization of O-2 p and Nb-4 d. The spontaneous polarization of Sr_2Nb_2O_7 in the [001]direction is 25 μC/cm~2, while for Sr_2Ta_2O_7, there was no spontaneous polarization in the paraelectric state. Finally, the effect of pressure on the piezoelectric properties were also investigated, the polarization of Sr_2Nb_2O_7 decreased linearly with the increase after pressure. All our preliminary results throw light on the nature of dielectric, piezoelectric properties,Born effective charge, and spontaneous polarization of Sr_2M_2O_7, it was helpful for experimental research, the development of new materials, and future applications. 相似文献
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通过对铌锌酸铅基铁电陶瓷(0.9-x)PZN-0.1BT-xPT,(x=.051,0.15)在0-450℃热膨胀行为的详细测量,结合其相应温度范围内的介电温谱,发现一个弱的一级相变过程,进而探讨了复合钙钛矿结构弛豫型铁电体中局域极化的转变特性。 相似文献
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β相聚偏二氟乙烯PVDF薄膜的制备和热光效应研究 总被引:1,自引:0,他引:1
采用溶液旋覆法制备β相PVDF铁电聚合物薄膜,利用X射线衍射仪、傅里叶红外光谱仪对薄膜晶形结构进行分析,并使用椭偏仪测定了溶液法制备的β相PVDF薄膜热光系数,同时对其热-光信号读出机制进行研究.结果表明,在60~120℃下结晶有利于β晶相的形成,而较高温度下主要形成γ晶相;薄膜的热光效应不仅与其热膨胀紧密相关,还受到温度变化趋势的影响,在20~100℃范围内,β相PVDF聚合物薄膜有较高的(负)热光系数约2.4~3.3×10-4/K,升温条件下测得的热光系数更高;在探测波长633 nm条件下,薄膜反射率变化可以线性地表征出薄膜温度的变化,基于薄膜热光效应的热-光信号读出机制是可行的. 相似文献
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通过对掺钛铌镁酸铅铁电陶瓷Pb(Mg1/3Nb2/3)0.8Ti0.2O3介电、铁电、热学行为及结构等的详细测量,发现这一材料由高温顺电态转变为弛豫型铁电态,表现出典型弥散性相变特征;由弛豫型铁电态转变为正常铁电态,则表现出一极相变特征。进而探讨了复合钙钛矿铁电体中极性微区的动态结构转变特征。 相似文献
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沉积温度对反应电子束蒸发TiO2薄膜结构和光学性能的影响 总被引:1,自引:0,他引:1
TiO2具有较高的折射率,在光学方面有着广泛的应用.文中采用等离子辅助反应电子束真空蒸镀法,以Ti为膜料、纯度为99.99%的O2为反应气体,在玻璃衬底上制备了TiO2薄膜.使用XRD、OM、SEM分别对50℃、150℃、300℃三个不同沉积温度下制备的薄膜及其经过450℃真空退火1 h后的结构进行了分析,并对薄膜的折射率进行测量.实验结果表明,提高沉积温度可以增加成膜原子的能量及其在衬底上的扩散能力,使沉积的薄膜结构平整致密,具有较高的折射率. 相似文献
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