Single Crystal Growth at Warwick

The work of the Superconductivity and Magnetism Group Warwick centres on the investigation of strongly correlated electron systems. The philosophy of the group has been to adopt a multi-pronged approach to the study of a range of superconductors and magnetic materials. High quality single crystals are essential for these investigations. In-house experimentation on single crystals is complemented by studies at central facilities using techniques such as neutron and x-ray scattering, muon spin resonance, and measurements in high magnetic fields. These studies are used to arrive at a unified picture of the physics of the materials of interest.We propose to continue to build on our successful crystal growth activities at Warwick. We will produce high quality single crystals of oxides, selenides, silicides and related materials. These include exotic superconductors, various low-dimensional and frustrated magnetic materials, and multiferroics. These crystals will be grown by the floating zone technique using the three optical mirror furnaces that we have at Warwick (two halogen lamp furnaces and one xenon arc lamp furnace). The optical mirror furnaces allow us to grow crystals under different growth conditions including various gas atmospheres, in pressures of up to 10 bars and at temperatures of up to 3000 C. Alternative techniques such as flux growth and chemical vapour transport will be used for the growth of single crystal materials when the floating zone technique is not suitable. A newly acquired tetra-arc furnace will be commissioned and the Czochralski technique will be used to produce single crystals of intermetallic materials.Some of the materials discussed in the proposal may never have been produced in the form of single crystal before. The preparation of crystals of these materials will necessarily require several growth attempts in order to optimise the growth conditions.The single crystals grown are to be used in all of our EPSRC funded work. The crystals will also be made available to other researchers within the UK and internationally. The crystal growth programme supports a wide collaborative network that we have built up over many years. The work will stimulate the formation of new collaborations.

The physics of Functional Materials, including the complex oxides, multiferroics, ferroelectrics, superconductors, and thermoelectrics to be grown as single crystals in this work hold tremendous potential to contribute to advances in technology. As single crystals these materials may be used in many applications including superconducting devices, spintronics, magnetic sensors, lasers, as magnetic refrigerants, as substrates, and as thermoelectrics. The impact on the high technology industrial sector of these materials is expected to be seen in the medium term. The research programme described in this proposal will have a significant impact on the education of students and early career researchers by exposing them to highly collaborative, interdisciplinary research environments and international user facilities. The project will have a significant impact on an emergent multifaceted partnership between Boston University (BU) and the University of Warwick. The two universities are engaged in a broad effort to form joint transatlantic interdisciplinary research programs. Active collaborations are being developed in several areas of mutual interest including materials physics and the present research proposal would play an important role in the internationalisation of materials research at both Warwick and BU. Our Regional Development Agency, Advantage West Midlands (and the European Regional Development Fund) has funded a Science City Initiative between the Universities of Warwick and Birmingham for research into Advanced Materials. The aim of this initiative is to establish the region as an international competitor in materials physics, undertaking world-class research in the development and characterisation of new materials for applications in a diverse range of industries. As part of this project the S&M Group has been successful in obtaining equipment for crystal growth and low temperature characterisation. The current proposal will enhance our capabilities in this area and stimulate research that will be beneficial to local, UK, and European companies. Job creation in the region in specialised science areas is a stated aim of the Science City Initiative and this project will have a significant impact on this in both the short and long term. In the short term, the high quality crystals produced in this project will benefit the work of a large number of researchers, both in the UK and worldwide. (See also letters of Support). In particular, several postgraduate students working for their M.Sc. or Ph.D. degrees will benefit from the expertise, training and the provision of crystals that will be made available as a result of this project. In the short to medium term, the impact of the proposed research work will be seen in the provision of trained research personnel to fill positions available in Universities in the niche area of single crystal growth, in central scientific facilities (Synchrotron, neutron and muon sources) and in post-doctoral and faculty positions at Universities in Condensed Matter Physics. There will also be benefits in terms of this project's impact on the ability of the investigators to obtain funding for further research from European and US funding agencies, as well as to build collaborative links with new partners.