Advanced Inorganic Functional Materials: Floating Zone Crystal Growth System

The development of new inorganic functional materials, needed for a range of applications, requires the understanding of structures and physical properties of the candidate phases.

On the structural side, high-quality large (cm-sized) single crystals are the best samples on which to solve and refine structures of such materials. The reason for this is two-fold. Firstly, single crystal diffraction has the advantage over powder diffraction in that the intensities of individual Bragg reflections can be measured reliably, whereas the latter suffers from peak overlap. Secondly, neutron diffraction is the method of choice for structure determination of functional materials in which the X-ray scattering is dominated by heavier cations and key information (atomic positions, occupancies, thermal displacement parameters) about the anions cannot be determined reliably. In addition, neutron diffraction can also probe long-range magnetic order. Large single crystals are needed due to the weaker interaction of matter with neutrons relative to X-rays.

For physical property measurements, large single crystals offer several advantages compared to working with powdered samples. For example, crystals can be oriented with respect to experimental probes in order to investigate the directionality and anisotropy of physical properties such as electrical or magnetic responses. In addition, property measurements on polycrystalline powered materials often suffer from grain boundary effects, which cannot always be separated from the response of the bulk of the material.

In this project we will establish a floating zone crystal growth system to produce high-quality samples of a range of important inorganic materials. These include materials for energy applications (fuel cells, photovoltaics, thermoelectrics) and those where electronic or magnetic ordering leads directly to exploitable properties such as piezoelectricity, sensing, under-water and medical imaging, gas separation, memristor and multiferroic memory applications. The information we gain on the structures and physical properties will help the exploitations of these compounds and give us the insight needed to design new generation of improved functional materials.

The objective of this project is to set up a floating zone crystal growth laboratory which will be used to prepare and orient high-quality large single crystals of inorganic functional materials ready for structure analysis and physical property measurements. This equipment will be applicable to the crystal growth of many different types of inorganic functional materials, including materials for energy applications (ionic and mixed ionic-electronic conductors, photovoltaics, thermoelectrics) and those where electronic or magnetic ordering leads directly to exploitable properties such as piezoelectricity, sensing, imaging, gas separation, memristor and multiferroic memory applications. Our ultimate goal will therefore be the delivery of new functional materials potentially exploitable in devices, which will arise from the new levels of understanding of the relevant structures and properties achieved through measurements on single crystals. Such developments could have significant economic and societal impact.

The project will have significant academic impact. Members of the Consortium have excellent track records in publishing academic research outputs in high-quality journals. In addition, subject-specific knowledge will be disseminated through presentations at international meetings and via electronic media.

This equipment suite will also have an important impact on people, through training and skills development. It will be the UK's first single crystal growth facility with hands-on access to external users. As such, it will contribute to the training of researchers through workshops on materials preparation and characterisation.