Ferroelectrics UK and Ireland 2025 update - Plenary Speaker Abstracts

Dear Colleagues,

Ahead of the Christmas break, please find further details below of the topics our excellent Keynote Speakers will cover at Ferroelectrics UK and Ireland 2025.

Keynote Speakers

Dr Lynette Keeney (Tyndall National Institute, University College Cork, Ireland): Uncovering Polar Vortex Topologies in Room Temperature Multiferroic Thin Films 

Aurivillius phase Bi6Ti3Fe1.5Mn0.5O18 (B6TFMO) is a rare room-temperature magnetoelectric multiferroic with promising applications in energy-efficient data storage. This presentation highlights the emergence of polar topological structures, including charged domain walls and polar vortices, near naturally occurring structural defects in B6TFMO. These defects alter internal elastic strain and electrostatic energy gradients, resulting in inhomogeneous polarisation distributions. Remarkably, these topologies form without artificial interfaces or external strain engineering. However, uncontrolled defect propagation leads to variability in defect type and density, presenting a challenge for reproducibility. To address this, B6TFMO thin films were synthesised on mis-cut vicinal sapphire substrates with varying off-axis angles (0.2°–10°) using chemical vapour deposition. X-ray diffraction and scanning transmission electron microscopy confirm that substrate mis-cut increases structural defect density, while piezoresponse force microscopy reveals modifications in ferroelectric domain size, polarisation orientation, and switching behaviour. These findings provide pathways to control defects and tailor novel topologies for advanced nanoelectronic applications.

Professor Ian M. Reaney (School of Chemical, Materials and Biological Engineering, University of Sheffield): High Permittivity Quasi-Linear Dielectrics for High Voltage and Temperature Applications in Power Electronics

Power electronics will play a central role in the impending energy transition from fossil fuels to electrification, which will profoundly change transport and energy distribution infrastructure.  New wide-bandgap semiconductor technologies provide active components that can operate at 200 ºC or above, allowing reductions in heatsink size and equipment weight. In this contribution, we review the underpinning crystal chemistry that facilitates not only the high breakdown strength required for capacitor technology in power electronics, but also the large energy density that such components need. The contribution establishes clear crystallochemical principles for the design of high voltage, high permittivity (> 500) capacitors that have significantly greater volumetric efficiency than incumbent devices based on medium permittivity ceramics such as CaZrO3 (~ 40). 

Professor Long-Qing Chen (Penn State University, USA; IEEE UFFC Distinguished Lecturer 2024): Thermodynamics and Phase-field Method of Ferroelectric Domains

The lecture discusses the thermodynamics and the phase-field method of ferroelectric crystals and their applications to modeling and predicting the stability of domain structures and their responses to mechanical and electric fields. It will start with the basic principles of classical thermodynamics and introduce the fundamental equation of thermodynamics for homogeneous ferroelectric crystals. The relations of the fundamental equations of thermodynamics, Landau theory of ferroelectrics, and the thermodynamic properties will then be discussed, including the dielectric, elastic, piezoelectric properties. It will then be followed by the discussion on the thermodynamics of inhomogeneous ferroelectric crystals containing domain structures involving long-range elastic and electrostatic interactions and domain wall energy. The contributions to thermodynamics from electronic and ionic defects will be briefly discussed. The last part of the lecture will be focused on the applications of the phase-field method of ferroelectric domain structures. Examples will be presented to illustrate the application of the phase-field method to interpreting and understanding experimentally observed ferroelectric domain structures and to providing guidance to experimental growth of thin films and characterization to discover new mesoscale domain states of materials, achieve dramatically enhanced properties, and uncover hidden functionality.

Reminder - Call for Papers

Also, just a quick reminder that Abstract submission opens on the 6th January 2025 and closes on the 31th January, and I'm pleased to inform you that the conference website is up and running: https://www.bath.ac.uk/events/ferroelectrics-uk-and-ireland-2025-conference/

Wishing you all a Merry Christmas.

James Roscow

Chair, UK and Ireland Ferroelectrics Network