高性能钙钛矿铁电固溶体材料热释电响应机制研究

Perovskite PMNT and PZNT ferroelectric single crytals are recently developed solid solution materials, which exhibit important promising applications and potential values. Since the Gulf War, the imaging features of the infrared focal plane array devices used by the United States military pose a challenge for the performance limitation of the commercial pyroelectric materials. This project utilizes the research advance of our coutry in relaxor ferroelectric single crystals, and systematically investigates the formation mechanisms of phase structure, ferroelectric domain configurration and crystal defects of the relaxor-based ferroelectric single crystals with compositions around the morphotropic phase boundary. We also research the influences of compositions, crystallographic direction, structure, ferroelectric domain configuration and its movement rule, and crystal defects on the pyroelectric response properties. Then we can find the physical principles of the high-performance pyroelectric response of the PMNT and PZNT single crystals, and estabilish physical model to describe the pyroelectric response mechanism. Via the combined materials treatment processing such as heat treatment, applied stress, electric field, radiation and so on, we can implement the controll of domain configuration and crystal defects of the as-grown single crystals, then pyroelectric properties of the PMNT and PZNT single crystals can be tailored futher. Based on this work, we estabilish effective techniques to modulate crystal structure and optimize pyroelectric performance.

PMNT和PZNT钙钛矿铁电固溶体单晶是新近开发而有重要应用前景和潜在价值的材料。海湾战争以来，美国军方使用的红外焦平面列阵器件的成像功能，对现有的热释电材料的性能局限提出了挑战。本项目利用我国在弛豫铁电单晶领域的研究优势，系统地研究准同型相界附近铁电体相、电畴结构、晶体缺陷的形成机理；研究组分、晶体学方向、结构、电畴组态及其运动规律、晶体缺陷对热释电性能的影响；从而挖掘PMNT和PZNT单晶高热释电响应的机理，建立描述热释电响应机制的物理模型。通过热处理、施加应力、电场、辐照等材料联合后处理工艺实现对电畴组态的调控和晶体缺陷的控制，优化单晶的热释电性能。在此基础上，建立起调控材料结构和优化材料热释电性能的有效方法。

PMNT和PZNT钙钛矿铁电固溶体单晶是新近开发而有重要应用前景和潜在价值的材料。海湾战争以来，美国军方使用的红外焦平面列阵器件的成像功能，对现有的热释电材料的性能局限提出了挑战。本项目利用我国在弛豫铁电单晶领域的研究优势，系统地研究准同型相界附近铁电体相、电畴结构、晶体缺陷的形成机理；研究组分、晶体学方向、结构、电畴组态及其运动规律、晶体缺陷对热释电性能的影响；从而挖掘弛豫铁电体高热释电响应的机理，建立描述热释电响应机制的物理模型。通过热处理、施加应力、电场、辐照等材料联合后处理工艺实现对电畴组态的调控和晶体缺陷的控制，优化铅基铁电体的热释电性能。在此基础上，建立起调控材料结构和优化材料热释电性能的有效方法。.本项目通过改进的Bridgman法生长PZNT单晶，通过反应烧结法制备PMNT陶瓷，通过B位氧化物预合成法制备PFSN基陶瓷。系统地研究了PZNT单晶、PMNT陶瓷、PFSN基陶瓷的介电、压电、铁电性能，优化了PZNT单晶、PMNT陶瓷、PFSN基陶瓷的制备工艺。.PZNT单晶、PMNT陶瓷、PFSN基陶瓷优良的电学性能和高的电阻率，有利于施加高直流电场进行极化处理，从而有望获得优良的热释电性能。本项目确立了弛豫铁电单晶和陶瓷的热释电性能的测试方法，获得了PZNT单晶、PMNT陶瓷、PFSN基陶瓷热释电性能的初步数据。研究了晶体生长方法、晶体组成、结构与PZNT单晶热释电性能的关系，陶瓷组成与PMNT陶瓷热释电性能的关系，陶瓷工艺、化学掺杂对PFSN基陶瓷热释电性能的影响，研究了电场、热处理等材料后处理工艺及工程化畴结构对材料性能的影响。发现PZNT单晶、PMNT陶瓷、PFSN基陶瓷具有较大的热释电系数、较高的电流响应优值、电压响应优值和探测优值，有望在非制冷红外探测和成像器件方面获得应用。