Nonlinear, Glassy, and Relaxor Behavior in Ferroelectrics

[805272]本项目研究三类铁电（FE）材料的性质。将被调查。它们包括质子玻璃和相关晶体、弛豫铁电体和钛铁电体。质子玻璃及其相关的氢键晶体表现出遍历性、质子隧穿、相共存和快速离子电导率等现象。钛基家族，因其优异的二次谐波产生特性而突出，存在有关FE畴和一维电导率的问题，而弛豫铁电体（具有随机位于适当位置的异价阳离子的晶体）则存在与部分或完全抑制FE跃迁有关的问题。属于这三个类别中的任何一个的不同材料将被调查。具体研究涉及使用各种技术，如量热法，四极微扰核磁共振，原子力显微镜，拉曼和布里渊光谱和光学测量等。该研究得益于大量合作者的参与，他们为该项目带来了额外的实验和理论专业知识。这项研究将带来的好处之一是提高了对各种铁电材料行为的理解。这将有助于它们与先进的技术设备相结合。研究生和博士后研究人员将在21世纪具有特殊就业机会的技术重要领域接受培训。这是对结晶铁电材料的基础性研究。该研究由研究生、博士后研究助理和外部合作者共同进行。从这个项目中获得的好处将是新的、改进的技术设备。学生和博士后研究人员将在21世纪具有特殊就业机会的领域接受良好的培训

9805272SchmidtIn this project the properties of three classes of ferroelectric (FE) materials. will be investigated. They include proton glasses and related crystals, relaxor ferroelectrics, and titanyl ferroelectrics. Proton glasses and related H-bonded crystals show such phenomena as ergodicity, proton tunneling, phase coexistence, and fast ion conductivity. The titanyl family, prominent because of excellent second harmonic generation properties, has questions concerning FE domains and one-dimensional conductivity, while relaxor ferroelectrics (crystals with unlike-valence cations randomly located at appropriate sites) pose problems relating to partly or fully suppressed FE transitions. Different materials belonging to any one of these three categories will be investigated. Specific studies involve the use of various techniques such as, calorimetry, quadrupole-perturbed nuclear magnetic resonance, atomic force microscopy, Raman and Brillouin spectroscopy and optical measurements, and others. The research benefits from the participation of a large number of collaborators who bring additional experimental and theoretical expertise to this project. Among the benefits that will result from this research are improved understandings of the behaviors of a large variety of ferroelectric materials. This will facilitate their incorporation in advanced technological devices. Graduate students and post doctoral research associates will receive training in an technologically important area with exceptional employment opportunities in the 21st Century.%%%This is a fundamental study of crystalline ferroelectric materials. The research is conducted with graduate students, post doctoral research associates and external collaborators. The benefits accruing from this project will be new, improved technological devices. Students and post doctoral research associates will receive excellent training in an area with exceptional employment opportunities during the 21st Century.**