A pre-characterisation facility for all excitations users developed through a study of quasiparticle breakdown in new relaxor ferroelectrics

铁电体是超声成像的核心组成部分，对医疗和工业应用都很重要。目前，这些器件的标准材料是铅基弛豫铁电体单晶。这些材料由于其特殊的压电性能、大的应变耐受性和单晶形式的抗开裂性，导致了一系列新的应用。然而，由于对环境的担忧，铅基晶体的使用正在逐步淘汰。需要发现新的材料来取代这些铅基单晶。该项目的科学重点将是利用中子光谱学研究无铅候选材料的晶格动力学，并将这些结果与材料的压电特性联系起来。设施发展的重点是双重的。首先，将开发成像技术，以研究样品的结晶度和化学均匀性，目标是在ALF测试站上为所有ISIS用户提供这种能力。其次，该项目的光谱部分需要结合大型数据集进行详细分析，与第一性原理建模代码集成，并进行分辨率卷积。这将使用isiss正在单独开发的PACE软件来实现。学生的参与将在科学调试阶段。

Ferroelectrics are a central component of ultrasound imaging important for medical and industrial applications. The standard material for thesedevices is currently single crystals of lead-based relaxor ferroelectrics. These materials have led to a new series of applications owing to theirexceptional piezoelectric properties, large tolerance to strain and resistance to cracking in single crystalline form. However, the use of lead basedcrystals is being phased out due to environmental concerns. New materials need to be discovered to replace these lead-based single crystals. The scientific focus of the project will be to investigate the lattice dynamics in lead-free candidate materials using neutron spectroscopy,and to relate these results to the materials piezoelectric properties. The facility development focus is twofold. First, imaging techniques will bedeveloped to allow sample crystallinity and chemical homogeneity to be investigated, with the goal of providing such a capability on the ALF teststation for use by all ISIS users. Second, the spectroscopy part of the project requires detailed analysis combining large datasets, integrationwith first-principles modelling codes, and resolution convolution. This will be achieved using the PACE software that is being developed at ISISseparately. The student's involvement will be at the scientific commissioning stage.