|Dr. Rebecca Boston|
|Dr. Julian Dean|
|Dr. Colin L. Freeman|
|Prof. SC Lenny Koh|
|Dr. Nicola Morley|
|Prof. Ian M. Reaney|
|Prof. Derek C. Sinclair|
Postdoctoral Research Fellows:
|Dr. Christopher Handley|
|Dr. Taofeeq |
|Dr. Giorgio Schileo|
|Dr. Whitney Schmidt|
|Dr. Brant Walkley|
|Dr. Fan Yang|
Rebecca Boston is a Lloyd’s Register/ Royal Academy of Engineering Research Fellow. She originally joined the department in 2014 as a postdoctoral research associate on the Substitution and Sustainability grant, before being awarded the Fellowship which started in December 2016. Rebecca did her PhD at the Bristol Centre for Functional Nanomaterials at the University of Bristol, working with Dr Simon Hall in the School of Chemistry. Her work is focussed on the use of novel synthetic templating methods (biological, solvent etc) to control the structure-function relationships in a variety of materials, including n-type thermoelectrics, high permittivity materials, and Li- and Na-ion batteries. She also works on the development of Cold Sintering techniques for ceramic materials, and has an interest in analytic transmission electron microscopy.
1) R. Boston, Z. Schnepp, Y. Nemoto, Y. Sakka, S. R. Hall, Science (2014), 344, 623-626.
In Situ TEM observation of a microcrucible mechanism of nanowire growth.
The growth of metal oxide nanowires can proceed via a number of mechanisms such as screw dislocation, vapour-liquid-solid process, or seeded growth. Transmission electron microscopy (TEM) can resolve nanowires but invariably lacks the facility for direct observation of how nanowires form. We used a transmission electron microscope equipped with an in situ heating stage to follow the growth of quaternary metal oxide nanowires. Video-rate imaging revealed barium carbonate nanoparticles diffusing through a porous matrix containing copper and yttrium oxides to subsequently act as catalytic sites for the outgrowth of Y2BaCuO5 nanowires on reaching the surface. The results suggest that sites on the rough surface of the porous matrix act as microcrucibles and thus provide insights into the mechanisms that drive metal oxide nanowire growth at high temperatures.
2) R. Boston, W. L. Schmidt, G. D. Lewin, A. C. Iyasara, Z. Lu, H. Zhang, D. C. Sinclair, I. M. Reaney, Chem Mater. (2017), 29, 265-280.
Protocols for the Fabrication, Characterization, and Optimization of n-Type Thermoelectric Ceramic Oxides
The development of oxides with high figure of merit, ZT, at modest temperatures (∼300–500 °C) is desirable for ceramic-based thermoelectric generator technology. Although ZT is a compound metric with contributions from thermal conductivity (κ), Seebeck coefficient (S), and electrical conductivity (σ), it has been empirically demonstrated that the key to developing thermoelectric n-type oxides is to optimize σ of the ceramic to ∼1000 S/cm at the operating temperature. This paper covers common aspects of ceramic processing: the potential pitfalls and how to avoid them. The problems associated with measuring κ, σ, and S to achieve reproducible and accurate values of ZT are discussed, as are future directions which should enable further optimization. Finally, we comment on how these protocols may be applied to other systems and structures.
3) R. Boston, P. Y. Foeller, D. C. Sinclair, I. M. Reaney, Inorg. Chem. (2017), 56, 542-547.
Synthesis of Barium Titanate Using Deep Eutectic Solvents
A deep eutectic solvent of malonic acid and choline chloride has been used to synthesize ferroelectric barium titanate. The barium titanate forms at 950 °C, mediated by the intermediate phases barium chloride and titanium dioxide. The materials sinter at a lower temperature than the solid-state equivalent while retaining comparable properties. This synthesis represents a flexible and widely applicable method which can be applied to a range of functional materials to produce nanoscale powders.
1) Design of a bilayer ceramic capacitor with low temperature coefficient of capacitance, PY Foeller, JS Dean, IM Reaney, DC Sinclair, Applied Physics Letters 109 (8), 082904 (2016)
2) Carbon uptake and distribution in Spark Plasma Sintering (SPS) processed Sm (Co, Fe, Cu, Zr), AJ Mackie, GD Hatton, HGC Hamilton, JS Dean, R Goodall, Materials Letters 171, 14-17 1 (2016)
3) A resource efficient design strategy to optimise the temperature coefficient of capacitance of BaTiO 3-based ceramics using finite element modelling, JS Dean, PY Foeller, IM Reaney, DC Sinclair, Journal of Materials Chemistry A 4 (18), 6896-6901, 1 (2016)
4) A sound idea: Manipulating domain walls in magnetic nanowires using surface acoustic waves, J Dean, MT Bryan, JD Cooper, A Virbule, JE Cunningham, TJ Hayward, Applied Physics Letters 107 (14), 142405, 1 (2015)
Ian M. Reaney joined the Department of Materials Science and Engineering in 1994, as a PDRA, then as a Lecturer from 1995 followed by eventual promotion to Professor in 2007. Ian was appointed to the Dyson Chair in Ceramics at the Materials Science and Engineering at the University of Sheffield in January 2017. He is also an Adjunct Professor at Pennsylvania State University, USA and at the University of Aveiro, Portugal. Ian has been awarded over £20M in career income for engineering research. His 300 scientific papers receive 1100 citations per year (more than 10,000 total citations), 23 papers having over 100 citations. He has given over 25 invited presentations a major conferences in the last 5 years. His career H-index = 52 (H5 = 38) (Googlescholar). He won 'best Knowledge Transfer Partnership based on EPSRC funded research’, 2008 and was the recipient of the Edward C. Henry award for best paper in the J. American Ceramics Society (Electronic Division) 2001.
Postdoctoral Research Fellows:
2) Next generation interatomic potentials for condensed systems, CM Handley, J Behler, Eur. Phys. J. B, 87, 152, 2014
1) Drivers of US toxicological footprints trajectory 1998–2013., SCL Koh, T Ibn-Mohammed, A Acquaye, K Feng, IM Reaney, K Hubacek, H Fujii, K Khatab, Scientific Reports 2016, 6, 39514.
2) Integrated hybrid life cycle assessment and supply chain environmental profile evaluations of lead-based (lead zirconate titanate) versus lead-free (potassium sodium niobate) piezoelectric ceramics, T Ibn-Mohammed, SCL Koh, IM Reaney, A Acquaye, D Wang, S Taylor, A Genovese, Energy & Environmental Science 2016, 9, (11), 3495-3520.
3) A Acquaye, K Feng, E Oppon, S Salhi, T Ibn-Mohammed, A Genovese, K Hubacek, Measuring the Environmental Sustainability Performance of Global Supply Chains: a Multi-Regional Input-Output analysis for Carbon, Sulphur Oxide and Water Footprints. Journal of Environmental Management 2016.
1) High ionic conductivity with low degradation in A-site Strontium-doped nonstoichiometric Sodium Bismuth Titanate perovskite, Chemistry of Materials, F. Yang, H. Zhang, L. Li, I. M. Reaney and D. C. Sinclair, 28 (2016) 5269-5273
2) Enhanced bulk conductivity of A-site divalent acceptor-doped non-stoichiometric sodium bismuth titanate, F. Yang, P. Wi, D. C. Sinclair, Solid State Ionics, 299 (2017) 38-45.