溶胶-凝胶法制备Pb(Zr1?xTix)O3复合梯度薄摸以及介电与热释电特性

"在Pt/Ti/SiO2/Si基片上用溶胶-凝胶法生长制备了PZT(Pb(Zr1-xTix)O3)复合梯度铁电薄膜． 薄膜最终结构由6层组成,"向上"梯度薄膜在Pt底电极上的第一层从PbZrO3开始,顶层是PZT(50/50),即第一层是PbZrO3,第二层PZT90/10 (10%Ti),第三层是PZT80/20,第四层PZT70/30,第五层PZT60/40,第六层PZT50/50．每一层与此相反的是"向下"梯度PZT薄膜．用X射线衍射、俄歇电子能谱和阻抗分析来研究梯度薄膜的结构与介电特性．600     

(111)取向生长Pb(Zr0:95Ti0:05)O3纳米晶薄膜的铁电与热释电特性

" 在Pt/Ti/SiO2/Si基片上用溶胶-凝胶法与快速退火工艺制备了300 nm厚的锆钛酸铅Pb(Zr0:95Ti0:05)O3 (PZT95/5)反铁电薄膜．结果显示600~700 ℃晶化处理的钙钛矿PZT95/5薄膜具有高度(111)取向生长特性．薄膜的电性能测量采用金属-铁电-金属电容器结构．在20 V电压作用下,600~700 ℃晶化处理的PZT95/5薄膜显示出饱和电滞回线．在1 kHz下,600、650和700 ℃晶化的薄膜介电常数与损耗分别为519与0.028、677与0.029、987     

Investigation on FR(LT)–FR(HT) phase transition and pyroelectric properties of pulsed laser deposited Pb(Zr0.93Ti0.07)O3 thin films

The preparation process, crystallinity and electrical properties of pulse laser deposited Pb(Zr_xTi_1−x)O₃ (PZT) thin films were investigated in this paper. PZT (x = 0.93) thin film samples deposited at different substrate temperatures were prepared. Si (1 1 0) was the substrate; Ag and YBCO were the top electrode and the bottom electrode respectively. The bottom electrode YBCO was deposited on the Si substrate by pulsed laser deposition (PLD), and then PZT was epitaxially deposited on YBCO also by PLD. After annealing, the top electrode Ag was prepared on PZT by thermal evaporation, and then the Ag/PZT/YBCO/Si structured thin films were obtained. The XRD and the analysis of their electrical characters showed that, when the substrate temperature was elevated from 600 °C to 800 °C, the crystallinity and electrical properties of PZT thin films became better and better, and the F_R(LT)–F_R(HT) phase transition of PZT (x = 0.93) thin films occurred at 62 °C. The PZT film deposited at 800 °C had the best pyroelectric properties, and when the F_R(LT)–F_R(HT) phase transition of this film occurred, the peak value of pyroelectric coefficient (p) was obtained, with a value of 1.96 × 10⁻⁶ C/(cm² K). The PZT film deposited at 800 °C had the highest remnant polarization (P_r) and the lowest coercive field (E_c), with the values of 34.3 μC/cm² and 41.7 kV/cm respectively.     

电场中三层铁电超晶格的物理性质研究

基于微分算符技术的相关有效场理论研究用伊辛模型描述的铁电三层超晶格的物理性质。讨论了电场对电极矩、电极化率、热电系数等物理性质的影响。     

Calix(8)arene LB Superlattices: Pyroelectric Molecular Baskets

Carboxyl and amino groups have been inserted into calix(8) arene rings in order to yield two materials which, when processed as alternate layer Langmuir-Blodgett assemblies, exhibit the pyroelectric effect. Such a temperature-dependent electric polarisation arises partially from the proton transfer between the acid and amine groups. The calix(8) arene system has been selected owing to the extreme tinness, of each monolayer(~1.0 nm), the resulting high density of acid-amine pairs and the very high thermal stability exhibited by calixarenes(typically m.p.>200℃).     

Simple macroscopic model of pyroelectric phenomenon in TGS single crystals in ferroelectric phase

A simple mathematical model of pyroelectric phenomena, for ideal ferroelectrics, is presented. Material constants for triglycine sulphate (TGS) are used to verify the model. The results of simulations were compared with the temperature characteristics of the pyroelectric coefficient measured for a TGS ferroelectric sample. Single crystal growth and preparation of samples and experimental procedure are also presented. The relatively good conformity of the model calculations with the measurements allow us to expect further useful application of the model in future work on ferroelectric single crystals.     

Research on Raman-scattering and Fabrication of Multilayer Thin Film with Different Structures and Components Based on Pt/Ti/Si3N4/SiO2/Si Substrate

选用三水醋酸铅、乙酰基丙酮酸锆、四异丙氧基钛、乙酰丙酮作初始材料,用同样的方法分别制备了锆钛酸铅(PZT)和钛酸铅(PT)两种固体前驱物. 采用改良型的溶胶-凝胶工艺技术,分别在不同的Pt-Ti-Si₃N₄-SiO₂-Si基底上,按照不同的组合方式,制备了三种多层薄膜：PZT、PT/PZT-PZT/PT、PT/PZT/-/PZT/PT. 较详细地讨论了薄膜制备的工艺技术,发现当凝胶通过烧结和干燥后变成固态物质时,薄膜内部存在着较大的残余应力,当薄膜在600 ºC下退火时其内部残余应力可以被减小. 通过拉曼     

一种实用化实时测温系统工作波长优化设计的进一步分析

基于Kirchhoff定律,依照测温系统的各主要技术参数与各主要技术指标(温度分辨力、测温灵敏度、相对测温灵敏度及测温准确度)之间的关系,对利用激光并采用钽酸锂热释电探测器作光电转换器件的实用化实时测温系统的工作波长进行了进一步的优化设计.实验表明,在测温范围400~1200 ℃内,系统的测温误差符合设计要求.     

2,4,6-Trimethylpyridinium perchlorate: Polar properties and correlations with molecular structure of organic–inorganic hybrid crystal

[(CH₃)₃C₅H₂NH][ClO₄] has been synthesized and characterized by X-ray (at 344, 245, 180 and 115 K), calorimetric, dilatometric, dielectric and pyroelectric measurements. At room temperature the crystal structure is polar, space group Pmn2₁. It consists of discrete disordered [ClO₄]^- anions and ordered trimethylpyridinium cations giving the 3D network of hydrogen bonds. The compound reveals a rich polymorphism in the solid state. It undergoes four solid–solid phase transitions: from phases I to II at 356/327 K (heating/cooling), II→III at 346/326, III→IV at 226 K and IV→V at 182/170 K. [(CH₃)₃C₅H₂NH][ClO₄] reveals a strong pyroelectric response over a wide temperature region (phases III, IV and V) with the spontaneous polarization changes (ΔP_s) of the order of . The spontaneous polarization is irreversible over all the polar phases, however, the magnitude of the ΔP_s in the vicinity of the phase transitions is characteristic of compounds with the ferroelectric order. The molecular mechanism of the successive phases transitions in the studied crystal is proposed.     

Analysis of temperature effect in dielectric response of electrostrictive polymers for pseudo-pyroelectric operations

Thanks to their flexibility and easy processability, electroactive polymers have gained a lot of attention over the last decades. More specifically, dielectric electrostrictive polymers have been demonstrated to provide interesting ways for mechanical actuation and energy harvesting or for electrocaloric applications. This Letter aims at presenting an additional application potential of such materials, showing their ability in terms of converting thermal energy into electrical energy. More particularly, it is shown that such materials, once polarized through the application of a bias electric field, allow a polarization variation with the temperature, yielding the so-called pseudo-pyroelectric effect. Theoretical analysis, supported by experiments, therefore demonstrates that such a material can exhibit pseudo-pyroelectric activity that can be tuned with the applied electric field.