Ferroelectrics & Crystallography Group
Research is carried out by the group, led by Professor Pam Thomas, on the fundamental physics of a wide range of ferroelectric crystals, including environmentally-friendly lead-free piezoelectrics, particularly those based on sodium bismuth titanate (NBT), and on novel optical properties revealed by the lithium niobate-tantalate solid solution. The group also continues its fundamental studies of non-linear optical crystals with tailored periodic domains for frequency conversion, which we study using specialised coherent X-ray imaging techniques in collaboration with Professor Jose Baruchel's group and ESRF, and is embarking on an investigation of the fundamental physics of novel multiferroic fluorides together with Warwick's Resonance Group and collaborators (Professor Jens Kreisel) at INPG Grenoble. The aim is the understanding of physical properties and phase transitions from the basis of structure in the most general sense, i.e. on the average crystallographic, local and “nano” scales. An approach is adopted in which relevant techniques are carefully chosen for the investigation of the problem at hand, frequently combining synchrotron and laboratory-based high-resolution X-ray diffraction, diffuse scattering and imaging, dielectric and optical measurements, neutron diffraction and NMR.
Professor Pam Thomas has been a member of staff in the Department of Physics at the University of Warwick since 1990 and a full professor since 2005. See here for more information about Pam.
New paper published in Phys. Rev. B. on Vibrational modes and overlap matrix of LiNb1-xTaxO3 mixed crystals.
New insight into the self-organised domains in BaTiO3 single crystals. An X-ray topography experiment and Optical Birefringence study are published in Phys. Rev. B.
Our latest PZT structural study, published in Nature Communications is highlighted at Phys.org. It provides the first experimental evidence for the missing phase boundary in PZT.
In collaboration with Oxford University a reproducible and low-cost method of modifying the optical properties of crystalline Lithium Tantalate enables highly accurate temperature readings, down to individual milli-kelvins, over a broad range of temperatures: -120°C to +680°C. More details here.
Selected images of optical birefringence recorded during heating of dodecasil-3C crystals from our collaboration with Richard Walton's group chosen to be the 2011 Journal of Applied Crystallography cover image.
New insight into the structure of PZT published in Phys. Rev. Lett. using Neutron diffraction on single crystals which have been grown for the first time. More information can be found here.